diff --git a/ChangeLog b/ChangeLog
index f5c2759daa..08f7ac2c64 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Sun Mar 24 12:55:47 2013  Narihiro Nakamura  <authornari@gmail.com>
+
+	* gc.c: We have no chance to expand the heap when lazy sweeping is
+	  restricted. So collecting is often invoked if there is not
+	  enough free space in the heap. Try to expand heap when this is
+	  the case.
+
 Sun Mar 24 11:03:31 2013  Tanaka Akira  <akr@fsij.org>
 
 	* test/ruby/test_require.rb: Remove temporally files in the tests.
diff --git a/gc.c b/gc.c
index 635e3ecadf..38bdcfd04b 100644
--- a/gc.c
+++ b/gc.c
@@ -2043,8 +2043,14 @@ gc_prepare_free_objects(rb_objspace_t *objspace)
 {
     int res;
 
-    if (objspace->flags.dont_lazy_sweep)
-        return garbage_collect(objspace);
+    if (objspace->flags.dont_lazy_sweep) {
+	if (heaps_increment(objspace)) {
+	    return;
+	}
+	else {
+	    return garbage_collect(objspace);
+	}
+    }
 
 
     if (!ready_to_gc(objspace)) return TRUE;