diff --git a/src/main/scala/app/AccountController.scala b/src/main/scala/app/AccountController.scala
index a013e64..bc0700b 100644
--- a/src/main/scala/app/AccountController.scala
+++ b/src/main/scala/app/AccountController.scala
@@ -12,7 +12,7 @@
   with SystemSettingsService with AccountService with RepositoryService with ActivityService
   with OneselfAuthenticator
 
-trait AccountControllerBase extends ControllerBase with FlashMapSupport {
+trait AccountControllerBase extends AccountManagementControllerBase with FlashMapSupport {
   self: SystemSettingsService with AccountService with RepositoryService with ActivityService
     with OneselfAuthenticator =>
 
@@ -105,30 +105,4 @@
     } else NotFound
   }
 
-  // TODO Merge with UserManagementController
-  private def updateImage(userName: String, fileId: Option[String]): Unit = {
-    fileId.map { fileId =>
-      val filename = "avatar." + FileUtil.getExtension(FileUploadUtil.getUploadedFilename(fileId).get)
-      FileUtils.moveFile(
-        FileUploadUtil.getTemporaryFile(fileId),
-        new java.io.File(getUserUploadDir(userName), filename)
-      )
-      updateAvatarImage(userName, Some(filename))
-    }
-  }
-
-  // TODO Merge with UserManagementController
-  private def uniqueUserName: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
-      getAccountByUserName(value).map { _ => "User already exists." }
-  }
-
-  // TODO Merge with UserManagementController
-  private def uniqueMailAddress(paramName: String = ""): Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
-      getAccountByMailAddress(value)
-        .filter { x => if(paramName.isEmpty) true else Some(x.userName) != params.get(paramName) }
-        .map    { _ => "Mail address is already registered." }
-  }
-
 }
diff --git a/src/main/scala/app/ControllerBase.scala b/src/main/scala/app/ControllerBase.scala
index 340a808..922105e 100644
--- a/src/main/scala/app/ControllerBase.scala
+++ b/src/main/scala/app/ControllerBase.scala
@@ -1,14 +1,18 @@
 package app
 
-import model.Account
-import util.Validations
+import _root_.util.Directory._
+import _root_.util.{FileUploadUtil, FileUtil, Validations}
 import org.scalatra._
 import org.scalatra.json._
 import org.json4s._
 import jp.sf.amateras.scalatra.forms._
+import org.apache.commons.io.FileUtils
+import model.Account
+import scala.Some
+import service.AccountService
 
 /**
- * Provides generic features for ScalatraServlet implementations.
+ * Provides generic features for controller implementations.
  */
 abstract class ControllerBase extends ScalatraFilter
   with ClientSideValidationFormSupport with JacksonJsonSupport with Validations {
@@ -87,4 +91,37 @@
 
 }
 
-case class Context(path: String, loginAccount: Option[Account], currentUrl: String)
\ No newline at end of file
+/**
+ * Context object for the current request.
+ */
+case class Context(path: String, loginAccount: Option[Account], currentUrl: String)
+
+/**
+ * Base trait for controllers which manages account information.
+ */
+trait AccountManagementControllerBase extends ControllerBase { self: AccountService =>
+
+  protected def updateImage(userName: String, fileId: Option[String]): Unit = {
+    fileId.map { fileId =>
+      val filename = "avatar." + FileUtil.getExtension(FileUploadUtil.getUploadedFilename(fileId).get)
+      FileUtils.moveFile(
+        FileUploadUtil.getTemporaryFile(fileId),
+        new java.io.File(getUserUploadDir(userName), filename)
+      )
+      updateAvatarImage(userName, Some(filename))
+    }
+  }
+
+  protected def uniqueUserName: Constraint = new Constraint(){
+    def validate(name: String, value: String): Option[String] =
+      getAccountByUserName(value).map { _ => "User already exists." }
+  }
+
+  protected def uniqueMailAddress(paramName: String = ""): Constraint = new Constraint(){
+    def validate(name: String, value: String): Option[String] =
+      getAccountByMailAddress(value)
+        .filter { x => if(paramName.isEmpty) true else Some(x.userName) != params.get(paramName) }
+        .map    { _ => "Mail address is already registered." }
+  }
+
+}
\ No newline at end of file
diff --git a/src/main/scala/app/UserManagementController.scala b/src/main/scala/app/UserManagementController.scala
index e8502f8..7ec77a7 100644
--- a/src/main/scala/app/UserManagementController.scala
+++ b/src/main/scala/app/UserManagementController.scala
@@ -10,7 +10,8 @@
 
 class UserManagementController extends UserManagementControllerBase with AccountService with AdminAuthenticator
 
-trait UserManagementControllerBase extends ControllerBase { self: AccountService with AdminAuthenticator =>
+trait UserManagementControllerBase extends AccountManagementControllerBase {
+  self: AccountService with AdminAuthenticator =>
   
   case class UserNewForm(userName: String, password: String, mailAddress: String, isAdmin: Boolean,
                          url: Option[String], fileId: Option[String])
@@ -77,31 +78,5 @@
       redirect("/admin/users")
     } getOrElse NotFound
   })
-
-  // TODO Merge with AccountController?
-  private def updateImage(userName: String, fileId: Option[String]): Unit = {
-    fileId.map { fileId =>
-      val filename = "avatar." + FileUtil.getExtension(FileUploadUtil.getUploadedFilename(fileId).get)
-      FileUtils.moveFile(
-        FileUploadUtil.getTemporaryFile(fileId),
-        new java.io.File(getUserUploadDir(userName), filename)
-      )
-      updateAvatarImage(userName, Some(filename))
-    }
-  }
-
-  // TODO Merge with AccountController?
-  private def uniqueUserName: Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
-      getAccountByUserName(value).map { _ => "User already exists." }
-  }
-
-  // TODO Merge with AccountController?
-  private def uniqueMailAddress(paramName: String = ""): Constraint = new Constraint(){
-    def validate(name: String, value: String): Option[String] =
-      getAccountByMailAddress(value)
-        .filter { x => if(paramName.isEmpty) true else Some(x.userName) != params.get(paramName) }
-        .map    { _ => "Mail address is already registered." }
-  }
   
 }
\ No newline at end of file