diff --git a/ChangeLog b/ChangeLog
index a867a5b36a..7b589d8dad 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,7 @@
-Fri Feb  8 19:19:55 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Fri Feb  8 19:22:13 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/iconv/iconv.c (rb_str_derive): uses rb_str_subseq() for byte
+	  length.  [ruby-dev:33653]
 
 	* ext/iconv/iconv.c (iconv_convert): added toidx argument to set
 	  encoding of successfully converted string.  [ruby-dev:33221]
diff --git a/ext/iconv/iconv.c b/ext/iconv/iconv.c
index 357a666abe..ed46234077 100644
--- a/ext/iconv/iconv.c
+++ b/ext/iconv/iconv.c
@@ -319,7 +319,7 @@ rb_str_derive(VALUE str, const char* ptr, int len)
     if (NIL_P(str))
 	return rb_str_new(ptr, len);
     if (RSTRING_PTR(str) + RSTRING_LEN(str) == ptr + len)
-	ret = rb_str_substr(str, ptr - RSTRING_PTR(str), len);
+	ret = rb_str_subseq(str, ptr - RSTRING_PTR(str), len);
     else
 	ret = rb_str_new(ptr, len);
     OBJ_INFECT(ret, str);