diff --git a/ChangeLog b/ChangeLog
index 7fb5ac6e0b..e46ff49664 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Tue Oct  8 13:53:21 2013  Masaki Matsushita  <glass.saga@gmail.com>
+
+	* array.c (rb_ary_uniq): use rb_hash_keys().
+
+	* internal.h: define rb_hash_keys() as internal API.
+
+	* hash.c (rb_hash_keys): ditto.
+
 Tue Oct  8 10:56:39 2013  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* cont.c: disable FIBER_USE_NATIVE on GNU/Hurd because it doesn't
diff --git a/array.c b/array.c
index 76289f41f6..e94eff5b0d 100644
--- a/array.c
+++ b/array.c
@@ -4130,13 +4130,7 @@ rb_ary_uniq(VALUE ary)
     }
     else {
 	hash = ary_make_hash(ary);
-	uniq = ary_new(rb_obj_class(ary), RHASH_SIZE(hash));
-	for (i=0; i<RARRAY_LEN(ary); i++) {
-	    st_data_t vv = (st_data_t)(v = rb_ary_elt(ary, i));
-	    if (st_delete(rb_hash_tbl_raw(hash), &vv, 0)) {
-		rb_ary_push(uniq, v);
-	    }
-	}
+	uniq = rb_hash_keys(hash);
     }
     ary_recycle_hash(hash);
 
diff --git a/hash.c b/hash.c
index 9eca54876f..d65a698fc2 100644
--- a/hash.c
+++ b/hash.c
@@ -1682,7 +1682,7 @@ keys_i(VALUE key, VALUE value, VALUE ary)
  *
  */
 
-static VALUE
+VALUE
 rb_hash_keys(VALUE hash)
 {
     VALUE ary;
diff --git a/internal.h b/internal.h
index f26a63dbf6..ad710d08d8 100644
--- a/internal.h
+++ b/internal.h
@@ -435,6 +435,7 @@ void rb_gc_writebarrier_remember_promoted(VALUE obj);
 /* hash.c */
 struct st_table *rb_hash_tbl_raw(VALUE hash);
 #define RHASH_TBL_RAW(h) rb_hash_tbl_raw(h)
+VALUE rb_hash_keys(VALUE hash);
 
 /* inits.c */
 void rb_call_inits(void);