diff --git a/string.c b/string.c
index c01f2e595b..962848e4a7 100644
--- a/string.c
+++ b/string.c
@@ -9400,7 +9400,7 @@ rb_enc_str_scrub(rb_encoding *enc, VALUE str, VALUE repl)
 		    rb_str_buf_cat(buf, rep, replen);
 		}
 		else {
-		    repl = rb_yield(rb_enc_str_new(p, e-p, enc));
+		    repl = rb_yield(rb_enc_str_new(p, clen, enc));
 		    repl = str_compat_and_valid(repl, enc);
 		    tainted |= OBJ_TAINTED_RAW(repl);
 		    rb_str_buf_cat(buf, RSTRING_PTR(repl), RSTRING_LEN(repl));
diff --git a/test/ruby/test_m17n.rb b/test/ruby/test_m17n.rb
index c610f71216..44f19254dc 100644
--- a/test/ruby/test_m17n.rb
+++ b/test/ruby/test_m17n.rb
@@ -1623,7 +1623,7 @@ class TestM17N < Test::Unit::TestCase
     assert_raise(ArgumentError){ u("\xE3\x81\x82\xE3\x81\x82\xE3\x81").scrub{u("\x81")} }
     assert_equal(e("\xA4\xA2\xA2\xAE"), e("\xA4\xA2\xA4").scrub{e("\xA2\xAE")})
 
-    assert_equal(u("\x81"), u("a\x81").scrub {|c| break c})
+    assert_equal(u("\x81"), u("a\x81c").scrub {|c| break c})
     assert_raise(ArgumentError) {u("a\x81").scrub {|c| c}}
   end
 
@@ -1641,8 +1641,8 @@ class TestM17N < Test::Unit::TestCase
                  "\xff".force_encoding(Encoding::UTF_32LE).
                  scrub)
     c = nil
-    assert_equal("?".encode(Encoding::UTF_16LE),
-                 "\x00\xD8".force_encoding(Encoding::UTF_16LE).
+    assert_equal("?\u3042".encode(Encoding::UTF_16LE),
+                 "\x00\xD8\x42\x30".force_encoding(Encoding::UTF_16LE).
                    scrub {|e| c = e; "?".encode(Encoding::UTF_16LE)})
     assert_equal("\x00\xD8".force_encoding(Encoding::UTF_16LE), c)
   end