diff --git a/src/main/java/org/ntlab/citrusserver/entities/Account.java b/src/main/java/org/ntlab/citrusserver/entities/Account.java
index 89d28bf..eb04687 100644
--- a/src/main/java/org/ntlab/citrusserver/entities/Account.java
+++ b/src/main/java/org/ntlab/citrusserver/entities/Account.java
@@ -28,8 +28,8 @@
     }
     @JsonIgnore
     public int getBookCount() {return bookcount;}
-
     public void setId(String i) {accountId = i;}
+
     @JsonIgnore
     public String getId() {return accountId;}
     public void setPassword(String p) {password = p;}
diff --git a/src/main/java/org/ntlab/citrusserver/repositories/AccountManager.java b/src/main/java/org/ntlab/citrusserver/repositories/AccountManager.java
index 4f5d087..1e76248 100644
--- a/src/main/java/org/ntlab/citrusserver/repositories/AccountManager.java
+++ b/src/main/java/org/ntlab/citrusserver/repositories/AccountManager.java
@@ -82,6 +82,18 @@
         }
     }
 
+    // 指定されたIDを変更する (PUT)
+    public void changeAccountId(String accountId, String newAccountId, String oldPassword, String token) {
+        if(accountToken.get(accountId).equals(token)) { //token比較
+            if(accounts.get(accountId).getPassword().equals(oldPassword)) { //password比較
+
+                accounts.get(accountId).setId(newAccountId);
+                accounts.put(newAccountId, accounts.get(accountId));
+                accounts.remove(accountId);
+            }
+        }
+    }
+
     // 指定されたIDのパスワードを変更する (PUT)
     public void changePassword(String accountId, String newPassword, String oldPassword, String token) {
         if(accountToken.get(accountId).equals(token)) { //token比較
@@ -120,7 +132,7 @@
             accounts.get(accountId).setAccountColor(newColor);
         }
     }
-    ////////////
+    ///////////
 
     // アカウントidとパスワードでログインし、tokenを返す (POST)
     public String login(String accountId, String password) {
diff --git a/src/main/java/org/ntlab/citrusserver/resources/AccountsRest.java b/src/main/java/org/ntlab/citrusserver/resources/AccountsRest.java
index 1e38ea0..de50990 100644
--- a/src/main/java/org/ntlab/citrusserver/resources/AccountsRest.java
+++ b/src/main/java/org/ntlab/citrusserver/resources/AccountsRest.java
@@ -84,6 +84,30 @@
 
     }
 
+    //accountのidを変更する(PUT)
+    @Path("/{account_id}")
+    @PUT
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)//bodyに入力する値がある時
+    public void changeAccountId(@PathParam("account_id") String accountId,
+                                @FormParam("new_account_id")String newAccountId,
+                                @FormParam("old_password")String oldPassword,
+                                @FormParam("token") String token){
+        //404
+        if (!accountManager.getAccountsID().contains(accountId)){ //account_idが存在しない時
+            var response = Response.status(Response.Status.NOT_FOUND).entity("IDが存在しません");//404
+            throw new WebApplicationException(response.build());
+        }
+        //成功
+        if(accountManager.checkToken(accountId, token)) {
+            accountManager.changeAccountId(accountId, newAccountId,oldPassword, token);
+            return;
+        }
+
+        //403
+        var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");//forbiddenは403
+        throw new WebApplicationException(response.build());
+    }
+
     //指定されたIDのパスワードを変更する (PUT)
     @Path("/{account_id}/password")
     @PUT
@@ -171,18 +195,6 @@
     }
     ///////////////////
 
-
-//////////
-// お気に入りの本のbook_idを削除する (DELETE)
-//    @Path("/{account_id}/favorites/{other_account_id}/{book_id}")
-//    @DELETE
-
-    // いいねした本のアカウントIDとbook_idを追加する(いいねした側に追加) (PUT)
-    //@Path("/{account_id}/favorites/{other_account_id}/{book_id}")
-//  @PUT
-
-
-
     // アカウントidとパスワードでログインし、tokenを返す (POST)
     @Path("/{account_id}/login")
     @POST