diff --git a/src/main/java/org/ntlab/citrusserver/repositories/BookManager.java b/src/main/java/org/ntlab/citrusserver/repositories/BookManager.java
index b1562c8..478547a 100644
--- a/src/main/java/org/ntlab/citrusserver/repositories/BookManager.java
+++ b/src/main/java/org/ntlab/citrusserver/repositories/BookManager.java
@@ -18,21 +18,11 @@
     private final List<IBookListener> iBookListeners = new ArrayList<>();
 
     //IBookListenerを追加
-    private void addListener(IBookListener iBookListener)
+    public void addListener(IBookListener iBookListener)
     {
         iBookListeners.add(iBookListener);
     }
 
-    //IBookListenerに通知する
-    private void notifyListener(Account account, Book book)
-    {
-        for(IBookListener iBookListener : iBookListeners)
-        {
-            iBookListener.bookChanged(account, book);
-        }
-    }
-
-
     @Autowired
     public BookManager(AccountManager accountManager) {
         this.accountManager = accountManager;
@@ -133,4 +123,13 @@
         }
 
     }
+
+    //IBookListenerに通知する
+    private void notifyListener(Account account, Book book)
+    {
+        for(IBookListener iBookListener : iBookListeners)
+        {
+            iBookListener.bookChanged(account, book);
+        }
+    }
 }
diff --git a/src/main/java/org/ntlab/citrusserver/resources/BooksRest.java b/src/main/java/org/ntlab/citrusserver/resources/BooksRest.java
index 934dc2d..b731b9e 100644
--- a/src/main/java/org/ntlab/citrusserver/resources/BooksRest.java
+++ b/src/main/java/org/ntlab/citrusserver/resources/BooksRest.java
@@ -61,7 +61,13 @@
             throw new WebApplicationException(response.build());
         }
         else{
-            return bookManager.createBook(account_id, title, color, publicity);
+            if (bookManager.createBook(account_id, title, color, publicity) == 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{
+                return bookManager.createBook(account_id, title, color, publicity);
+            }
         }
     }
 
@@ -119,7 +125,7 @@
         }
         else{
             if (bookManager.getTitle(account_id, book_id) == null) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("アカウントが見つかりません");
+                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{
@@ -161,7 +167,7 @@
         }
         else{
             if (bookManager.getPublicity(account_id, book_id) == null) {
-                var response = Response.status(Response.Status.FORBIDDEN).entity("アカウントが見つかりません");
+                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{