diff --git a/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java b/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java
index c65fa4f..b6452cb 100644
--- a/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java
+++ b/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java
@@ -2,17 +2,20 @@
 
 import org.ntlab.citrusserver.entities.Account;
 import org.ntlab.citrusserver.entities.Book;
+import org.springframework.stereotype.Repository;
 
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.regex.*;
 
+
+@Repository
 public class PublicBookManager implements IBookListener{
 
     private final BookManager bookManager;
 
-    private HashSet<Book> publicBooks = new HashSet<>();
+    private final HashMap<String, HashSet<Book>> publicBooks = new HashMap<>();
 
     public PublicBookManager(BookManager bookManager) {
         this.bookManager = bookManager;
@@ -20,15 +23,21 @@
     }
 
     public ArrayList<Book> getAllPublicBooks(){
-        return new ArrayList<>(this.publicBooks);
+        ArrayList<Book> books = new ArrayList<>();
+        for(HashSet<Book> bookSet : publicBooks.values()){
+            books.addAll(bookSet);
+        }
+        return books;
     }
 
     public ArrayList<Book> searchBooksByTitle(String title){
         ArrayList<Book> books = new ArrayList<>();
         var ptn = Pattern.compile(title);
-        for(Book book : this.publicBooks){
-            if(ptn.matcher(book.getTitle()).find()){
-                books.add(book);
+        for(HashSet<Book> bookSet : publicBooks.values()){
+            for(Book book : bookSet){
+                if(ptn.matcher(book.getTitle()).find()){
+                    books.add(book);
+                }
             }
         }
         return books;
@@ -40,9 +49,11 @@
 
     public ArrayList<Book> searchBooksByAccount(String accountId){
         ArrayList<Book> books = new ArrayList<>();
-        for(Book book : this.publicBooks){
-            if(book.getAccountId().equals(accountId)){
-                books.add(book);
+        for(HashSet<Book> bookSet : publicBooks.values()){
+            for(Book book : bookSet){
+                if(book.getAccountId().equals(accountId)){
+                    books.add(book);
+                }
             }
         }
         return books;
@@ -65,9 +76,12 @@
     @Override
     public void bookChanged(Account account, Book book) {
         if(book.getPublicity()){
-            this.publicBooks.add(book);
+            if(!publicBooks.containsKey(account.getId())){
+                publicBooks.put(account.getId(), new HashSet<>());
+            }
+            this.publicBooks.get(account.getId()).add(book);
         } else{
-            this.publicBooks.remove(book);
+            this.publicBooks.get(account.getId()).remove(book);
         }
     }
 }