diff --git a/ext/strscan/strscan.c b/ext/strscan/strscan.c
index e843e54..490689b 100644
--- a/ext/strscan/strscan.c
+++ b/ext/strscan/strscan.c
@@ -321,8 +321,7 @@ strscan_set_string(VALUE self, VALUE str)
 
     Data_Get_Struct(self, struct strscanner, p);
     StringValue(str);
-    p->str = rb_str_dup(str);
-    rb_obj_freeze(p->str);
+    p->str = str;
     p->curr = 0;
     CLEAR_MATCH_STATUS(p);
     return str;
diff --git a/test/strscan/test_stringscanner.rb b/test/strscan/test_stringscanner.rb
index f2feb6d..ec6c699 100644
--- a/test/strscan/test_stringscanner.rb
+++ b/test/strscan/test_stringscanner.rb
@@ -168,6 +168,26 @@ class TestStringScanner < Test::Unit::TestCase
     assert_equal 0, s.pos
   end
 
+  def test_string_set_is_equal
+    name = 'tenderlove'
+
+    s = StringScanner.new(name)
+    assert_equal name.object_id, s.string.object_id
+
+    s.string = name
+    assert_equal name.object_id, s.string.object_id
+  end
+
+  def test_string_append
+    s = StringScanner.new('tender')
+    s << 'love'
+    assert_equal 'tenderlove', s.string
+
+    s.string = 'tender'
+    s << 'love'
+    assert_equal 'tenderlove', s.string
+  end
+
   def test_pos
     s = StringScanner.new('test string')
     assert_equal 0, s.pos