diff --git a/include/limonp/StdExtension.hpp b/include/limonp/StdExtension.hpp
index cf00e94..38200ab 100644
--- a/include/limonp/StdExtension.hpp
+++ b/include/limonp/StdExtension.hpp
@@ -3,24 +3,8 @@
 
 #include <map>
 
-#ifdef __APPLE__
 #include <unordered_map>
 #include <unordered_set>
-#elif(__cplusplus >= 201103L)
-#include <unordered_map>
-#include <unordered_set>
-#elif defined _MSC_VER
-#include <unordered_map>
-#include <unordered_set>
-#else
-#include <tr1/unordered_map>
-#include <tr1/unordered_set>
-namespace std {
-using std::tr1::unordered_map;
-using std::tr1::unordered_set;
-}
-
-#endif
 
 #include <set>
 #include <string>