diff --git a/src/main/scala/app/RepositoryViewerController.scala b/src/main/scala/app/RepositoryViewerController.scala
index 285c50e..120081c 100644
--- a/src/main/scala/app/RepositoryViewerController.scala
+++ b/src/main/scala/app/RepositoryViewerController.scala
@@ -2,7 +2,7 @@
 
 import util.Directory._
 import util.Implicits._
-import util.{JGitUtil, FileTypeUtil, CompressUtil}
+import _root_.util.{ReadableRepositoryAuthenticator, JGitUtil, FileTypeUtil, CompressUtil}
 import service._
 import org.scalatra._
 import java.io.File
@@ -12,13 +12,13 @@
 import org.eclipse.jgit.treewalk._
 
 class RepositoryViewerController extends RepositoryViewerControllerBase 
-  with RepositoryService with AccountService
+  with RepositoryService with AccountService with ReadableRepositoryAuthenticator
 
 /**
  * The repository viewer.
  */
 trait RepositoryViewerControllerBase extends ControllerBase { 
-  self: RepositoryService with AccountService =>
+  self: RepositoryService with AccountService with ReadableRepositoryAuthenticator =>
   
   // TODO separate to AccountController?
   /**
@@ -33,37 +33,37 @@
   /**
    * Displays the file list of the repository root and the default branch.
    */
-  get("/:owner/:repository") {
+  get("/:owner/:repository")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     
     fileList(owner, repository)
-  }
+  })
   
   /**
    * Displays the file list of the repository root and the specified branch.
    */
-  get("/:owner/:repository/tree/:id") {
+  get("/:owner/:repository/tree/:id")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     
     fileList(owner, repository, params("id"))
-  }
+  })
   
   /**
    * Displays the file list of the specified path and branch.
    */
-  get("/:owner/:repository/tree/:id/*") {
+  get("/:owner/:repository/tree/:id/*")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     
     fileList(owner, repository, params("id"), multiParams("splat").head)
-  }
+  })
   
   /**
    * Displays the commit list of the specified branch.
    */
-  get("/:owner/:repository/commits/:branch"){
+  get("/:owner/:repository/commits/:branch")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val branchName = params("branch")
@@ -77,12 +77,12 @@
           view.helpers.date(commit1.time) == view.helpers.date(commit2.time)
         }, page, hasNext)
     }
-  }
+  })
   
   /**
    * Displays the commit list of the specified resource.
    */
-  get("/:owner/:repository/commits/:branch/*"){
+  get("/:owner/:repository/commits/:branch/*")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val branchName = params("branch")
@@ -97,13 +97,13 @@
           view.helpers.date(commit1.time) == view.helpers.date(commit2.time)
         }, page, hasNext)
     }
-  }
+  })
   
   
   /**
    * Displays the file content of the specified branch or commit.
    */
-  get("/:owner/:repository/blob/:id/*"){
+  get("/:owner/:repository/blob/:id/*")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val id         = params("id") // branch name or commit id
@@ -140,12 +140,12 @@
         repo.html.blob(id, repositoryInfo, path.split("/").toList, content, new JGitUtil.CommitInfo(revCommit))
       }
     }
-  }
+  })
   
   /**
    * Displays details of the specified commit.
    */
-  get("/:owner/:repository/commit/:id"){
+  get("/:owner/:repository/commit/:id")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val id         = params("id")
@@ -155,22 +155,22 @@
       repo.html.commit(id, new JGitUtil.CommitInfo(revCommit),
           getRepository(owner, repository, servletContext).get, JGitUtil.getDiffs(git, id))
     }
-  }
+  })
   
   /**
    * Displays tags.
    */
-  get("/:owner/:repository/tags"){
+  get("/:owner/:repository/tags")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     
     repo.html.tags(getRepository(owner, repository, servletContext).get)
-  }
+  })
   
   /**
    * Download repository contents as an archive.
    */
-  get("/:owner/:repository/archive/:name"){
+  get("/:owner/:repository/archive/:name")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val name       = params("name")
@@ -206,7 +206,7 @@
     } else {
       BadRequest
     }
-  }
+  })
   
   /**
    * Provides HTML of the file list.
diff --git a/src/main/scala/app/SettingsController.scala b/src/main/scala/app/SettingsController.scala
index 460f95e..32f54d0 100644
--- a/src/main/scala/app/SettingsController.scala
+++ b/src/main/scala/app/SettingsController.scala
@@ -46,7 +46,7 @@
   /**
    * Save the repository options.
    */
-  post("/:owner/:repository/settings/options", optionsForm){ form =>
+  post("/:owner/:repository/settings/options", optionsForm)(ownerOnly { form =>
     val owner      = params("owner")
     val repository = params("repository")
     
@@ -54,7 +54,7 @@
     saveRepositoryOptions(owner, repository, form.description, form.defaultBranch, form.repositoryType)
     
     redirect("%s/%s/settings/options".format(owner, repository))
-  }
+  })
   
   /**
    * Display the Collaborators page.
diff --git a/src/main/scala/app/UsersController.scala b/src/main/scala/app/UsersController.scala
index 3ca0075..92aceeb 100644
--- a/src/main/scala/app/UsersController.scala
+++ b/src/main/scala/app/UsersController.scala
@@ -2,11 +2,12 @@
 
 import model._
 import service._
+import util.AdminOnlyAuthenticator
 import jp.sf.amateras.scalatra.forms._
 
-class UsersController extends UsersControllerBase with AccountService
+class UsersController extends UsersControllerBase with AccountService with AdminOnlyAuthenticator
 
-trait UsersControllerBase extends ControllerBase { self: AccountService =>
+trait UsersControllerBase extends ControllerBase { self: AccountService with AdminOnlyAuthenticator =>
   
   // TODO ユーザ名の先頭に_は使えないようにする＆利用可能文字チェック
   case class UserForm(userName: String, password: String, mailAddress: String, userType: Int, url: Option[String])
@@ -27,15 +28,15 @@
     "url"         -> trim(label("URL"          , optional(text(maxlength(200)))))
   )(UserForm.apply)
   
-  get("/admin/users"){
+  get("/admin/users")(adminOnly {
     admin.html.userlist(getAllUsers())
-  }
+  })
   
-  get("/admin/users/_new"){
+  get("/admin/users/_new")(adminOnly {
     admin.html.useredit(None)
-  }
+  })
   
-  post("/admin/users/_new", newForm){ form =>
+  post("/admin/users/_new", newForm)(adminOnly { form =>
     val currentDate = new java.sql.Date(System.currentTimeMillis)
     createAccount(Account(
         userName       = form.userName, 
@@ -48,14 +49,14 @@
         lastLoginDate  = None))
         
     redirect("/admin/users")
-  }
+  })
   
-  get("/admin/users/:userName/_edit"){
+  get("/admin/users/:userName/_edit")(adminOnly {
     val userName = params("userName")
     admin.html.useredit(getAccountByUserName(userName))
-  }
+  })
   
-  post("/admin/users/:name/_edit", editForm){ form =>
+  post("/admin/users/:name/_edit", editForm)(adminOnly { form =>
     val userName = params("userName")
     val currentDate = new java.sql.Date(System.currentTimeMillis)
     updateAccount(getAccountByUserName(userName).get.copy(
@@ -66,7 +67,7 @@
         updatedDate    = currentDate))
     
     redirect("/admin/users")
-  }
+  })
   
   def unique: Constraint = new Constraint(){
     def validate(name: String, value: String): Option[String] =
diff --git a/src/main/scala/app/WikiController.scala b/src/main/scala/app/WikiController.scala
index d9ed92b..b6d62e0 100644
--- a/src/main/scala/app/WikiController.scala
+++ b/src/main/scala/app/WikiController.scala
@@ -1,15 +1,15 @@
 package app
 
 import service._
-import util.{CollaboratorsOnlyAuthenticator, JGitUtil}
+import util.{WritableRepositoryAuthenticator, ReadableRepositoryAuthenticator, JGitUtil}
 import util.Directory._
 import jp.sf.amateras.scalatra.forms._
 
 class WikiController extends WikiControllerBase 
-  with WikiService with RepositoryService with AccountService with CollaboratorsOnlyAuthenticator
+  with WikiService with RepositoryService with AccountService with WritableRepositoryAuthenticator with ReadableRepositoryAuthenticator
 
 trait WikiControllerBase extends ControllerBase {
-  self: WikiService with RepositoryService with CollaboratorsOnlyAuthenticator =>
+  self: WikiService with RepositoryService with WritableRepositoryAuthenticator with ReadableRepositoryAuthenticator =>
 
   // TODO ユーザ名の先頭に_は使えないようにする
   case class WikiPageEditForm(pageName: String, content: String, message: Option[String], currentPageName: String)
@@ -28,7 +28,7 @@
     "currentPageName" -> trim(label("Current page name"  , text(required)))
   )(WikiPageEditForm.apply)
   
-  get("/:owner/:repository/wiki"){
+  get("/:owner/:repository/wiki")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     
@@ -36,9 +36,9 @@
       case Some(page) => wiki.html.wiki("Home", page, getRepository(owner, repository, servletContext).get, isWritable(owner, repository))
       case None => redirect("/%s/%s/wiki/Home/_edit".format(owner, repository))
     }
-  }
+  })
   
-  get("/:owner/:repository/wiki/:page"){
+  get("/:owner/:repository/wiki/:page")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val pageName   = params("page")
@@ -47,9 +47,9 @@
       case Some(page) => wiki.html.wiki(pageName, page, getRepository(owner, repository, servletContext).get, isWritable(owner, repository))
       case None => redirect("/%s/%s/wiki/%s/_edit".format(owner, repository, pageName)) // TODO URLEncode
     }
-  }
+  })
   
-  get("/:owner/:repository/wiki/:page/_history"){
+  get("/:owner/:repository/wiki/:page/_history")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val page       = params("page")
@@ -58,9 +58,9 @@
       wiki.html.wikihistory(Some(page),
         JGitUtil.getCommitLog(git, "master", path = page + ".md")._1, getRepository(owner, repository, servletContext).get)
     }
-  }
+  })
   
-  get("/:owner/:repository/wiki/:page/_compare/:commitId"){
+  get("/:owner/:repository/wiki/:page/_compare/:commitId")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val page       = params("page")
@@ -70,9 +70,9 @@
       wiki.html.wikicompare(Some(page),
         getWikiDiffs(git, commitId(0), commitId(1)), getRepository(owner, repository, servletContext).get)
     }
-  }
+  })
   
-  get("/:owner/:repository/wiki/_compare/:commitId"){
+  get("/:owner/:repository/wiki/_compare/:commitId")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val commitId   = params("commitId").split("\\.\\.\\.")
@@ -81,9 +81,9 @@
       wiki.html.wikicompare(None,
         getWikiDiffs(git, commitId(0), commitId(1)), getRepository(owner, repository, servletContext).get)
     }
-  }
+  })
   
-  get("/:owner/:repository/wiki/:page/_edit")(collaboratorsOnly {
+  get("/:owner/:repository/wiki/:page/_edit")(writableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val page       = params("page")
@@ -92,7 +92,7 @@
         getWikiPage(owner, repository, page), getRepository(owner, repository, servletContext).get)
   })
   
-  post("/:owner/:repository/wiki/_edit", editForm)(collaboratorsOnly { form =>
+  post("/:owner/:repository/wiki/_edit", editForm)(writableRepository { form =>
     val owner      = params("owner")
     val repository = params("repository")
     
@@ -102,14 +102,14 @@
     redirect("%s/%s/wiki/%s".format(owner, repository, form.pageName))
   })
   
-  get("/:owner/:repository/wiki/_new")(collaboratorsOnly {
+  get("/:owner/:repository/wiki/_new")(writableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     
     wiki.html.wikiedit("", None, getRepository(owner, repository, servletContext).get)
   })
   
-  post("/:owner/:repository/wiki/_new", newForm)(collaboratorsOnly { form =>
+  post("/:owner/:repository/wiki/_new", newForm)(writableRepository { form =>
     val owner      = params("owner")
     val repository = params("repository")
     
@@ -119,7 +119,7 @@
     redirect("%s/%s/wiki/%s".format(owner, repository, form.pageName))
   })
   
-  get("/:owner/:repository/wiki/:page/_delete")(collaboratorsOnly {
+  get("/:owner/:repository/wiki/:page/_delete")(writableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val page       = params("page")
@@ -129,14 +129,14 @@
     redirect("%s/%s/wiki".format(owner, repository))
   })
   
-  get("/:owner/:repository/wiki/_pages"){
+  get("/:owner/:repository/wiki/_pages")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     
     wiki.html.wikipages(getWikiPageList(owner, repository), getRepository(owner, repository, servletContext).get, isWritable(owner, repository))
-  }
+  })
   
-  get("/:owner/:repository/wiki/_history"){
+  get("/:owner/:repository/wiki/_history")(readableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     
@@ -144,15 +144,15 @@
       wiki.html.wikihistory(None,
         JGitUtil.getCommitLog(git, "master")._1, getRepository(owner, repository, servletContext).get)
     }
-  }
+  })
   
-  post("/:owner/:repository/wiki/_preview"){
+  post("/:owner/:repository/wiki/_preview")(writableRepository {
     val owner      = params("owner")
     val repository = params("repository")
     val content    = params("content")
     contentType = "text/html"
     view.helpers.markdown(content, getRepository(owner, repository, servletContext).get, true)
-  }
+  })
   
   /**
    * Constraint for the wiki page name.
diff --git a/src/main/scala/util/Authenticator.scala b/src/main/scala/util/Authenticator.scala
index e2749bf..2696869 100644
--- a/src/main/scala/util/Authenticator.scala
+++ b/src/main/scala/util/Authenticator.scala
@@ -8,7 +8,10 @@
  */
 trait OwnerOnlyAuthenticator { self: ControllerBase =>
 
-  protected def ownerOnly(action: => Any) = {
+  protected def ownerOnly(action: => Any) = { authenticate(action) }
+  protected def ownerOnly[T](action: T => Any) = (form: T) => authenticate({action(form)})
+
+  private def authenticate(action: => Any) = {
     {
       context.loginAccount match {
         case Some(x) if(x.userType == AccountService.Administrator) => action
@@ -17,16 +20,6 @@
       }
     }
   }
-
-  protected def ownerOnly[T](action: T => Any) = {
-    (form: T) => {
-      context.loginAccount match {
-        case Some(x) if(x.userType == AccountService.Administrator) => action(form)
-        case Some(x) if(request.getRequestURI.split("/")(1) == x.userName) => action(form)
-        case _ => redirect("/signin")
-      }
-    }
-  }
 }
 
 /**
@@ -34,7 +27,10 @@
  */
 trait UsersOnlyAuthenticator { self: ControllerBase =>
 
-  protected def usersOnly(action: => Any) = {
+  protected def usersOnly(action: => Any) = { authenticate(action) }
+  protected def usersOnly[T](action: T => Any) = (form: T) => authenticate({action(form)})
+
+  private def authenticate(action: => Any) = {
     {
       context.loginAccount match {
         case Some(x) => action
@@ -42,12 +38,21 @@
       }
     }
   }
+}
 
-  protected def usersOnly[T](action: T => Any) = {
-    (form: T) => {
+/**
+ * Allows only administrators.
+ */
+trait AdminOnlyAuthenticator { self: ControllerBase =>
+
+  protected def adminOnly(action: => Any) = { authenticate(action) }
+  protected def adminOnly[T](action: T => Any) = (form: T) => authenticate({action(form)})
+
+  private def authenticate(action: => Any) = {
+    {
       context.loginAccount match {
-        case Some(x) => action(form)
-        case None    => redirect("/signin")
+        case Some(x) if(x.userType == AccountService.Administrator) => action
+        case _ => redirect("/signin")
       }
     }
   }
@@ -56,41 +61,44 @@
 /**
  * Allows only collaborators and administrators.
  */
-trait CollaboratorsOnlyAuthenticator { self: ControllerBase with RepositoryService =>
+trait WritableRepositoryAuthenticator { self: ControllerBase with RepositoryService =>
 
-  protected def collaboratorsOnly(action: => Any) = {
-    {
+  protected def writableRepository(action: => Any) = { authenticate(action) }
+  protected def writableRepository[T](action: T => Any) = (form: T) => authenticate({action(form)})
+
+  private def authenticate(action: => Any) = {
+      val paths = request.getRequestURI.split("/")
       context.loginAccount match {
         case Some(x) if(x.userType == AccountService.Administrator) => action
-        case Some(x) if(request.getRequestURI.split("/")(1) == x.userName) => action
-        case Some(x) => {
-          val paths = request.getRequestURI.split("/")
-          if(getCollaborators(paths(1), paths(2)).contains(x.userName)){
-            action
-          } else {
-            redirect("/signin")
-          }
-        }
-        case None => redirect("/signin")
+        case Some(x) if(paths(1) == x.userName) => action
+        case Some(x) if(getCollaborators(paths(1), paths(2)).contains(x.userName)) => action
+        case _ => redirect("/signin")
       }
-    }
   }
+}
 
-  protected def collaboratorsOnly[T](action: T => Any) = {
-    (form: T) => {
-      context.loginAccount match {
-        case Some(x) if(x.userType == AccountService.Administrator) => action(form)
-        case Some(x) if(request.getRequestURI.split("/")(1) == x.userName) => action(form)
-        case Some(x) => {
-          val paths = request.getRequestURI.split("/")
-          if(getCollaborators(paths(1), paths(2)).contains(x.userName)){
-            action(form)
-          } else {
-            redirect("/signin")
-          }
+/**
+ * Allows only the repository owner and administrators.
+ */
+trait ReadableRepositoryAuthenticator { self: ControllerBase with RepositoryService =>
+
+  protected def readableRepository(action: => Any) = { authenticate(action) }
+  protected def readableRepository[T](action: T => Any) = (form: T) => authenticate({action(form)})
+
+  private def authenticate(action: => Any) = {
+    {
+      val paths = request.getRequestURI.split("/")
+      val repository = getRepository(paths(1), paths(2), servletContext)
+      if(repository.get.repository.repositoryType == RepositoryService.Public){
+        action
+      } else {
+        context.loginAccount match {
+          case Some(x) if(x.userType == AccountService.Administrator) => action
+          case Some(x) if(paths(1) == x.userName) => action
+          case Some(x) if(getCollaborators(paths(1), paths(2)).contains(x.userName)) => action
+          case _ => redirect("/")
         }
-        case None => redirect("/signin")
       }
     }
   }
-}
\ No newline at end of file
+}