diff --git a/time.c b/time.c
index 9f009b5a15..1c5fb87dad 100644
--- a/time.c
+++ b/time.c
@@ -2453,6 +2453,7 @@ obj2subsecx(VALUE obj, VALUE *subsecx)
     else {
         divmodv(num_exact(obj), INT2FIX(1), &obj, &subsec);
         *subsecx = w2v(rb_time_magnify(v2w(subsec)));
+	RB_GC_GUARD(subsec);
     }
     return obj2ubits(obj, 6); /* vtm->sec */
 }