diff --git a/a8/commonrank.h b/a8/commonrank.h
index 1810208..085bd41 100644
--- a/a8/commonrank.h
+++ b/a8/commonrank.h
@@ -81,31 +81,31 @@ namespace a8
     };
 
     template <typename T>
-    a8::CommonRank<T>& ForceCreateCommonRankList(std::map<long long, a8::CommonRank<T>>& rank_list,
+    a8::CommonRank<T>* ForceCreateCommonRankList(std::map<long long, a8::CommonRank<T>>& rank_list,
                                                  long long key,
                                                  std::function<bool (const T*, const T*)> cmp_func,
                                                  size_t max_num)
     {
         auto itr = rank_list.find(key);
         if (itr != rank_list.end()) {
-            return itr->second;
+            return &itr->second;
         }
         rank_list[key] = a8::CommonRank<T>(cmp_func, max_num);
-        return rank_list[key];
+        return &rank_list[key];
     }
 
     template <typename T>
-    static a8::CommonRank<T>& ForceCreateCommonRankList(std::map<std::string, a8::CommonRank<T>>& rank_list,
+    static a8::CommonRank<T>* ForceCreateCommonRankList(std::map<std::string, a8::CommonRank<T>>& rank_list,
                                                         const std::string& key,
                                                         std::function<bool (const T*, const T*)> cmp_func,
                                                         size_t max_num)
     {
         auto itr = rank_list.find(key);
         if (itr != rank_list.end()) {
-            return itr->second;
+            return &itr->second;
         }
         rank_list[key] = a8::CommonRank<T>(cmp_func, max_num);
-        return rank_list[key];
+        return &rank_list[key];
     }
 
 }