diff --git a/ChangeLog b/ChangeLog
index 181815b4a3..a5eccc49e6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Jun 21 05:37:39 2013  Koichi Sasada  <ko1@atdot.net>
+
+	* gc.c (gc_prof_sweep_timer_stop): accumulate sweep time only when
+	  record->gc_time > 0.
+
 Fri Jun 21 00:37:31 2013  Tanaka Akira  <akr@fsij.org>
 
 	* ext/bigdecimal: Workaround fix for bigdecimal test failures caused
diff --git a/gc.c b/gc.c
index 4528318fb4..44326d53e7 100644
--- a/gc.c
+++ b/gc.c
@@ -5086,13 +5086,17 @@ gc_prof_sweep_timer_stop(rb_objspace_t *objspace)
     }
     if (objspace->profile.run) {
 	double sweep_time;
+
 	gc_profile_record *record = gc_prof_record(objspace);
 
-	if (record->gc_time > 0 || GC_PROFILE_MORE_DETAIL) {
-	    /* need to accumulate for lazy sweep */
+	if (record->gc_time > 0) {
 	    sweep_time = elapsed_time_from(objspace->profile.gc_sweep_start_time);
+	    /* need to accumulate GC time for lazy sweep after gc() */
 	    record->gc_time += sweep_time;
 	}
+	else if (GC_PROFILE_MORE_DETAIL) {
+	    sweep_time = elapsed_time_from(objspace->profile.gc_sweep_start_time);
+	}
 
 #if GC_PROFILE_MORE_DETAIL
 	record->gc_sweep_time += sweep_time;