diff --git a/ChangeLog b/ChangeLog
index 500e0e9b11..daa5c82713 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sun Mar 21 09:22:10 2010  Tanaka Akira  <akr@fsij.org>
+
+	* object.c (rb_obj_hash): use LONG2FIX to avoid Bignum allocation.
+
 Sat Mar 20 22:51:46 2010  Tanaka Akira  <akr@fsij.org>
 
 	* string.c (rb_str_sum): use UCHAR_MAX.
diff --git a/object.c b/object.c
index 0421824202..f473fe1e4f 100644
--- a/object.c
+++ b/object.c
@@ -101,7 +101,7 @@ rb_obj_hash(VALUE obj)
 {
     VALUE oid = rb_obj_id(obj);
     st_index_t h = rb_hash_end(rb_hash_start(NUM2LONG(oid)));
-    return LONG2NUM(h);
+    return LONG2FIX(h);
 }
 
 /*