diff --git a/ChangeLog b/ChangeLog
index 7f73649c05..22c634d152 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jan 26 10:45:19 2005  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* win32/win32.c (flock_winnt, flock_win95): unlock file even if
+	  LOCK_NB is specified.
+
 Tue Jan 25 23:10:48 2005  Hidetoshi NAGAI  <nagai@ai.kyutech.ac.jp>
 
 	* ext/tk: merge tcltklib for Ruby/Tk installation control
diff --git a/win32/win32.c b/win32/win32.c
index e8fea80729..9de71d7a25 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -289,6 +289,7 @@ flock_winnt(VALUE self, int argc, VALUE* argv)
 			  0, LK_LEN, LK_LEN, &o), i);
 	break;
       case LOCK_UN:		/* unlock lock */
+      case LOCK_UN|LOCK_NB:	/* unlock is always non-blocking, I hope */
 	LK_ERR(UnlockFileEx(fh, 0, LK_LEN, LK_LEN, &o), i);
 	break;
       default:            /* unknown */
@@ -316,6 +317,7 @@ flock_win95(VALUE self, int argc, VALUE* argv)
 	LK_ERR(LockFile(fh, 0, 0, LK_LEN, LK_LEN), i);
 	break;
       case LOCK_UN:
+      case LOCK_UN|LOCK_NB:
 	LK_ERR(UnlockFile(fh, 0, 0, LK_LEN, LK_LEN), i);
 	break;
       default: