diff --git a/ChangeLog b/ChangeLog
index f9d1e8ac5b..773d07e38c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Wed Feb  5 13:29:01 2014  Koichi Sasada  <ko1@atdot.net>
+
+	* string.c (rb_str_free): use FL_TEST(str, STR_SHARED) directly
+	  because str is not embed.
+
+	* string.c (str_replace): remove `FL_SET(str, STR_SHARED)' line
+	  because STR_SET_SHARED() set STR_SHARED.
+
 Wed Feb  5 13:18:08 2014  Koichi Sasada  <ko1@atdot.net>
 
 	* internal.h: remove macros STR_NOCAPA and STR_NOCAPA_P().
diff --git a/string.c b/string.c
index 929ba516ff..0110c0a3a0 100644
--- a/string.c
+++ b/string.c
@@ -915,7 +915,8 @@ rb_str_free(VALUE str)
 	st_data_t fstr = (st_data_t)str;
 	st_delete(frozen_strings, &fstr, NULL);
     }
-    if (!STR_EMBED_P(str) && !STR_SHARED_P(str)) {
+
+    if (!STR_EMBED_P(str) && !FL_TEST(str, STR_SHARED)) {
 	ruby_sized_xfree(STR_HEAP_PTR(str), STR_HEAP_SIZE(str));
     }
 }
@@ -1009,7 +1010,6 @@ str_replace(VALUE str, VALUE str2)
 	STR_SET_NOEMBED(str);
 	RSTRING(str)->as.heap.len = len;
 	RSTRING(str)->as.heap.ptr = RSTRING_PTR(str2);
-	FL_SET(str, STR_SHARED);
 	STR_SET_SHARED(str, shared);
     }
     else {