diff --git a/src/main/java/org/ntlab/citrusserver/entities/Book.java b/src/main/java/org/ntlab/citrusserver/entities/Book.java
index c182121..c68c40e 100644
--- a/src/main/java/org/ntlab/citrusserver/entities/Book.java
+++ b/src/main/java/org/ntlab/citrusserver/entities/Book.java
@@ -17,7 +17,7 @@
         this.title = title;
         this.publicity = publicity;
         this.color = color;
-        
+
         this.time = time;
     }
 
diff --git a/src/main/java/org/ntlab/citrusserver/repositories/ScheduleManager.java b/src/main/java/org/ntlab/citrusserver/repositories/ScheduleManager.java
index 760568e..7874daf 100644
--- a/src/main/java/org/ntlab/citrusserver/repositories/ScheduleManager.java
+++ b/src/main/java/org/ntlab/citrusserver/repositories/ScheduleManager.java
@@ -98,4 +98,22 @@
         if(newBookId == null)newBookId = 0;
         schedules.get(accountId).get(year).get(month).get(day).get(scheduleId).setBookId(newBookId);
     }
+
+    public void deleteSchedules(String accountId){
+        schedules.remove(accountId);
+    }
+
+    public void deleteScheduleBookId(String accountId, Integer bookId){
+        for(int year : schedules.get(accountId).keySet()){
+            for (int month : schedules.get(accountId).get(year).keySet()){
+                for(int day : schedules.get(accountId).get(year).get(month).keySet()){
+                    for (int scheduleId : schedules.get(accountId).get(year).get(month).get(day).keySet()){
+                        if(schedules.get(accountId).get(year).get(month).get(day).get(scheduleId).getBookId().equals(bookId)){
+                            schedules.get(accountId).get(year).get(month).get(day).get(scheduleId).setBookId(0);
+                        }
+                    }
+                }
+            }
+        }
+    }
 }