diff --git a/src/main/java/org/ntlab/citrusserver/repositories/TodoManager.java b/src/main/java/org/ntlab/citrusserver/repositories/TodoManager.java
index 2bb0edc..a60d082 100644
--- a/src/main/java/org/ntlab/citrusserver/repositories/TodoManager.java
+++ b/src/main/java/org/ntlab/citrusserver/repositories/TodoManager.java
@@ -158,9 +158,9 @@
      * @param year 年
      * @param month 月
      * @param day 日
-     * @param todo 追加するべきtodo
+     * @param title 追加するべきtodoのタイトル
      */
-    public int addTodo(String accountId, int bookId, int year, int month, int day, Todo todo){
+    public int addTodo(String accountId, int bookId, int year, int month, int day, String title){
         if(!todos.containsKey(accountId)){
             todos.put(accountId, new HashMap<>());
         }
@@ -181,10 +181,11 @@
             nextTodoId.put(accountBook, 0);
         }
 
-        int tmp = nextTodoId.get(accountBook);
-        todos.get(accountId).get(bookId).get(year).get(month).get(day).put(tmp, todo);
-        nextTodoId.put(accountBook, tmp + 1);
-        return tmp;
+        int todoId = nextTodoId.get(accountBook);
+        Todo newTodo = new Todo(title, false, year, month, day, todoId);
+        todos.get(accountId).get(bookId).get(year).get(month).get(day).put(todoId, newTodo);
+        nextTodoId.put(accountBook, todoId + 1);
+        return todoId;
     }
 
     /**
@@ -192,14 +193,14 @@
      * @param accountId アカウントのid
      * @param bookId 本のid
      * @param yearMonthDay 年月日を-で区切った文字列(yyyy-mm-dd)
-     * @param todo 追加したいtodo
+     * @param title 追加したいtodoのタイトル
      */
-    public int addTodo(String accountId, int bookId, String yearMonthDay, Todo todo){
+    public int addTodo(String accountId, int bookId, String yearMonthDay, String title){
         String[] yearMonthDays = yearMonthDay.split("-");
         int year = Integer.parseInt(yearMonthDays[0]);
         int month = Integer.parseInt(yearMonthDays[1]);
         int day = Integer.parseInt(yearMonthDays[2]);
-        return addTodo(accountId, bookId, year, month, day, todo);
+        return addTodo(accountId, bookId, year, month, day, title);
     }
 
     /**