diff --git a/ChangeLog b/ChangeLog
index b8026542ad..12c6962407 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Mar  1 00:12:49 2011  Tajima Akio <artonx@yahoo.co.jp>
+
+	* include/ruby/win32.h: define WIN32 if neither _WIN64 nor WIN32 
+	  defined. it forces to use push/pop for pack(4) pragma.
+	
 Mon Feb 28 23:52:13 2011  CHIKANAGA Tomoyuki  <nagachika00@gmail.com>
 
 	* test/testunit/test_rake_integration.rb (test_with_rake_runner):
diff --git a/include/ruby/win32.h b/include/ruby/win32.h
index 9b1c46de18..051e9e9814 100644
--- a/include/ruby/win32.h
+++ b/include/ruby/win32.h
@@ -34,6 +34,9 @@ extern "C" {
 #if defined(__cplusplus) && defined(_MSC_VER)
 extern "C++" {			/* template without extern "C++" */
 #endif
+#if !defined(_WIN64) && !defined(WIN32)
+#define WIN32
+#endif
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #if defined(__cplusplus) && defined(_MSC_VER)