diff --git a/ChangeLog b/ChangeLog
index beff20e875..0ee31f6a3d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Mon Jan 21 14:32:10 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* transcode.c (str_transcode): initialize transcoder in
+	  rb_transcoding.  [ruby-dev:33234]
+
+	* transcode_data.h (rb_transcoding): transcoder constified.
+
 Mon Jan 21 12:50:02 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* eval.c, gc.c (setjmp): sigsetjmp is a macro on cygwin.
diff --git a/transcode.c b/transcode.c
index e36e6c1461..370bd06c33 100644
--- a/transcode.c
+++ b/transcode.c
@@ -311,6 +311,8 @@ str_transcode(int argc, VALUE *argv, VALUE *self)
 	return -1;
     }
 
+    my_transcoding.transcoder = my_transcoder;
+
     while (!final_encoding) { /* loop for multistep transcoding */
 	/* later, maybe use smaller intermediate strings for very long strings */
 	if (!(my_transcoder = transcode_dispatch(from_e, to_e))) {
diff --git a/transcode_data.h b/transcode_data.h
index 34f298853f..f025b4e6fe 100644
--- a/transcode_data.h
+++ b/transcode_data.h
@@ -59,7 +59,7 @@ typedef struct byte_lookup {
 /* dynamic structure, one per conversion (similar to iconv_t) */
 /* may carry conversion state (e.g. for iso-2022-jp) */
 typedef struct rb_transcoding {
-    struct rb_transcoder *transcoder;
+    const struct rb_transcoder *transcoder;
     VALUE ruby_string_dest; /* the String used as the conversion destination,
 			       or NULL if something else is being converted */
     unsigned char *(*flush_func)(struct rb_transcoding*, int, int);