diff --git a/src/main/java/org/ntlab/citrusserver/resources/BooksRest.java b/src/main/java/org/ntlab/citrusserver/resources/BooksRest.java
index 3398b0b..6e8982c 100644
--- a/src/main/java/org/ntlab/citrusserver/resources/BooksRest.java
+++ b/src/main/java/org/ntlab/citrusserver/resources/BooksRest.java
@@ -39,19 +39,9 @@
     @Produces(MediaType.APPLICATION_JSON)
     public  HashMap<Integer, Book> getBooks(@PathParam("account_id") String account_id, @QueryParam("token") String token){
 
-        if(accountManager.getAccount(account_id) == null){
-            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
-            throw new WebApplicationException(response.build());
-        }
-        else{
-            if(!accountManager.checkToken(account_id, token)) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
-                throw new WebApplicationException(response.build());
-            }
-            else{
-                return bookManager.getBooks(account_id);
-            }
-        }
+        accountCheck(account_id);
+        tokenCheck(account_id, token);
+        return bookManager.getBooks(account_id);
     }
 
     @Path("/{account_id}/books")
@@ -60,19 +50,9 @@
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)  // postmanのbodyに入力する値がある時
     public Book createBook(@PathParam("account_id") String account_id, @FormParam("title") String title, @FormParam("color") String color, @FormParam("publicity") Boolean publicity, @FormParam("token") String token) {
 
-        if (accountManager.getAccount(account_id) == null){
-            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
-            throw new WebApplicationException(response.build());
-        }
-        else{
-            if(!accountManager.checkToken(account_id, token)) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
-                throw new WebApplicationException(response.build());
-            }
-            else {
-                return bookManager.createBook(account_id, title, color, publicity);
-            }
-        }
+        accountCheck(account_id);
+        tokenCheck(account_id, token);
+        return bookManager.createBook(account_id, title, color, publicity);
     }
 
 
@@ -83,19 +63,9 @@
     @Produces(MediaType.APPLICATION_JSON)
     public Book getBook(@PathParam("account_id") String account_id, @PathParam("book_id") Integer book_id, @QueryParam("token") String token){
 
-        if (accountManager.getAccount(account_id) == null){
-            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
-            throw new WebApplicationException(response.build());
-        }
-        else{
-            if(!accountManager.checkToken(account_id, token)) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
-                throw new WebApplicationException(response.build());
-            }
-            else{
-                return bookManager.getBook(account_id, book_id);
-            }
-        }
+        accountCheck(account_id);
+        tokenCheck(account_id, token);
+        return bookManager.getBook(account_id, book_id);
     }
   /// 本の削除
     @Path("/{account_id}/books/{book_id}")
@@ -104,21 +74,11 @@
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
     public String deleteBook(@PathParam("account_id") String account_id, @PathParam("book_id") Integer book_id, @QueryParam("token") String token){
 
-        if(accountManager.getAccount(account_id) == null){
-            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
-            throw new WebApplicationException(response.build());
-        }
-        else{
-            if(!accountManager.checkToken(account_id, token)) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
-                throw new WebApplicationException(response.build());
-            }
-            else{
-                todoManager.deleteAllTodosByBookId(account_id, book_id);//削除時、Todoも消す
-                bookManager.deleteBook(account_id, book_id);
-                return "success";
-            }
-        }
+        accountCheck(account_id);
+        tokenCheck(account_id, token);
+        todoManager.deleteAllTodosByBookId(account_id, book_id);//削除時、Todoも消す
+        bookManager.deleteBook(account_id, book_id);
+        return "success";
     }
 
 /// /{account_id}/books/{book_id}/title
@@ -128,19 +88,9 @@
     @Produces(MediaType.TEXT_PLAIN)
     public String getTitle(@PathParam("account_id") String account_id, @PathParam("book_id") Integer book_id, @QueryParam("token") String token){
 
-        if (accountManager.getAccount(account_id) == null) {
-            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
-            throw new WebApplicationException(response.build());
-        }
-        else{
-            if(!accountManager.checkToken(account_id, token)) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
-                throw new WebApplicationException(response.build());
-            }
-            else{
-                return bookManager.getTitle(account_id, book_id);
-            }
-        }
+        accountCheck(account_id);
+        tokenCheck(account_id, token);
+        return bookManager.getTitle(account_id, book_id);
     }
 
   /// 本のタイトル変更
@@ -150,20 +100,10 @@
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
     public String putTitle(@PathParam("account_id") String account_id, @PathParam("book_id") Integer book_id, @FormParam("title") String title, @FormParam("token") String token){
 
-        if(accountManager.getAccount(account_id) == null){
-            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
-            throw new WebApplicationException(response.build());
-        }
-        else{
-            if(!accountManager.checkToken(account_id, token)) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
-                throw new WebApplicationException(response.build());
-            }
-            else{
-                bookManager.putTitle(account_id, book_id, title);
-                return "success";
-            }
-        }
+        accountCheck(account_id);
+        tokenCheck(account_id, token);
+        bookManager.putTitle(account_id, book_id, title);
+        return "success";
     }
 
 /// /accounts/{account_id}/books/{book_id}/public
@@ -173,19 +113,9 @@
     @Produces(MediaType.TEXT_PLAIN)
     public Boolean getPublicity(@PathParam("account_id") String account_id, @PathParam("book_id") Integer book_id, @QueryParam("token") String token){
 
-        if (accountManager.getAccount(account_id) == null) {
-            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
-            throw new WebApplicationException(response.build());
-        }
-        else{
-            if(!accountManager.checkToken(account_id, token)) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
-                throw new WebApplicationException(response.build());
-            }
-            else{
-                return bookManager.getPublicity(account_id, book_id);
-            }
-        }
+        accountCheck(account_id);
+        tokenCheck(account_id, token);
+        return bookManager.getPublicity(account_id, book_id);
     }
 
   /// 公開情報を変更する
@@ -195,20 +125,10 @@
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
     public String putPublicity(@PathParam("account_id") String account_id, @PathParam("book_id") Integer book_id, @FormParam("publicity") Boolean publicity, @FormParam("token") String token){
 
-        if(accountManager.getAccount(account_id) == null){
-            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
-            throw new WebApplicationException(response.build());
-        }
-        else{
-            if(!accountManager.checkToken(account_id, token)) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
-                throw new WebApplicationException(response.build());
-            }
-            else{
-                bookManager.putPublicity(account_id, book_id, publicity);
-                return "success";
-            }
-        }
+        accountCheck(account_id);
+        tokenCheck(account_id, token);
+        bookManager.putPublicity(account_id, book_id, publicity);
+        return "success";
     }
 
 /// /accounts/{account_id}/books/{book_id}/color
@@ -218,24 +138,27 @@
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
     public String putColor(@PathParam("account_id") String account_id, @PathParam("book_id") Integer book_id, @FormParam("color") String color, @FormParam("token") String token){
 
-        if(accountManager.getAccount(account_id) == null){
-            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
-            throw new WebApplicationException(response.build());
-        }
-        else{
-            if(!accountManager.checkToken(account_id, token)) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
-                throw new WebApplicationException(response.build());
-            }
-            else{
-                bookManager.putColor(account_id, book_id, color);
-                return "success";
-            }
-        }
+        accountCheck(account_id);
+        tokenCheck(account_id, token);
+        bookManager.putColor(account_id, book_id, color);
+        return "success";
     }
 
     ///---------------------------------------------------------------------
     ///private
     ///---------------------------------------------------------------------
 
+    private void accountCheck(String account_id){
+        if(accountManager.getAccount(account_id) == null){
+            var response = Response.status(Response.Status.NOT_FOUND).entity("アカウントが見つかりません");
+            throw new WebApplicationException(response.build());
+        }
+    }
+
+    private void tokenCheck(String account_id, String token){
+        if(!accountManager.checkToken(account_id, token)) {
+            var response = Response.status(Response.Status.FORBIDDEN).entity("認証失敗");
+            throw new WebApplicationException(response.build());
+        }
+    }
 }
\ No newline at end of file