diff --git a/sprintf.c b/sprintf.c
index 13d999f3ae..44b85200b1 100644
--- a/sprintf.c
+++ b/sprintf.c
@@ -584,7 +584,7 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt)
 #endif
 		len = (int)(p - start + 1); /* including parenthesis */
 		if (id) {
-		    rb_raise(rb_eArgError, "name%.*s after <%s>",
+		    rb_raise(rb_eArgError, "named%.*s after <%s>",
 			     len, start, rb_id2name(id));
 		}
 		id = rb_intern3(start + 1, len - 2 /* without parenthesis */, enc);
diff --git a/test/ruby/test_sprintf.rb b/test/ruby/test_sprintf.rb
index 218d2188b7..7d125fca43 100644
--- a/test/ruby/test_sprintf.rb
+++ b/test/ruby/test_sprintf.rb
@@ -325,10 +325,15 @@ class TestSprintf < Test::Unit::TestCase
 
   def test_named
     assert_equal("value", sprintf("%<key>s", :key => "value"))
-    assert_raise(ArgumentError) {sprintf("%1$<key2>s", :key => "value")}
-    assert_raise(ArgumentError) {sprintf("%<key><key2>s", :key => "value")}
+    e = assert_raise(ArgumentError) {sprintf("%1$<key2>s", :key => "value")}
+    assert_equal("named<key2> after numbered", e.message)
+    e = assert_raise(ArgumentError) {sprintf("%<key><key2>s", :key => "value")}
+    assert_equal("named<key2> after <key>", e.message)
     assert_equal("value", sprintf("%{key}", :key => "value"))
-    assert_raise(ArgumentError) {sprintf("%1${key2}", :key => "value")}
+    e = assert_raise(ArgumentError) {sprintf("%1${key2}", :key => "value")}
+    assert_equal("named{key2} after numbered", e.message)
+    e = assert_raise(ArgumentError) {sprintf("%<key>{key2}", :key => "value")}
+    assert_equal("named{key2} after <key>", e.message)
     assert_equal("value{key2}", sprintf("%{key}{key2}", :key => "value"))
   end
 end