diff --git a/src/main/java/org/ntlab/citrusserver/repositories/BookManager.java b/src/main/java/org/ntlab/citrusserver/repositories/BookManager.java
index af3fb10..779fa8b 100644
--- a/src/main/java/org/ntlab/citrusserver/repositories/BookManager.java
+++ b/src/main/java/org/ntlab/citrusserver/repositories/BookManager.java
@@ -18,9 +18,9 @@
     }
 
     //本の一覧を返す
-    public HashMap<String, HashMap<Integer, Book>> getBooks()
+    public HashMap<Integer, Book> getBooks(String accountId)
     {
-        return booksMap;
+        return booksMap.get(accountId);
     }
 
     //本の新規作成