diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c
index b60827fa..da6f6174 100644
--- a/ext/stringio/stringio.c
+++ b/ext/stringio/stringio.c
@@ -760,7 +760,7 @@ strio_get_lineno(VALUE self)
  *   lineno = new_line_number -> new_line_number
  *
  * Sets the current line number in +self+ to the given +new_line_number+;
- * see {Line Number}[rdoc-ref:IO@Line+Number].
+ * see {Line Number}[rdoc-ref:StringIO@Line+Number].
  */
 static VALUE
 strio_set_lineno(VALUE self, VALUE lineno)