diff --git a/lib/helper/opUtilHelper.php b/lib/helper/opUtilHelper.php
index 5a17e9930..bf9c7a155 100644
--- a/lib/helper/opUtilHelper.php
+++ b/lib/helper/opUtilHelper.php
@@ -311,24 +311,24 @@ function op_format_date($date, $format = 'd', $culture = null, $charset = null)
 {
   define('SF_AUTO_LINK_RE', '~
     (                       # leading text
-      <\w+.*?>|             #   leading HTML tag, or
+      <[0-9A-Za-z]+.*?>|    #   leading HTML tag, or
       [^=!:\'"/]|           #   leading punctuation, or
       ^|                    #   beginning of line, or
-      \s?                   #   leading whitespaces
+      \ ?                   #   leading whitespaces
     )
     (
       (?:https?://)|        # protocol spec, or
       (?:www\.)             # www.*
     )
     (
-      [-\w]+                   # subdomain or domain
-      (?:\.[-\w]+)*            # remaining subdomains or domain
-      (?::\d+)?                # port
+      [-0-9A-Za-z]+            # subdomain or domain
+      (?:\.[-0-9A-Za-z]+)*     # remaining subdomains or domain
+      (?::[0-9]+)?             # port
       \/?
       [a-zA-Z0-9_\-\/.,:;\~\?@&=+$%#!()]*
     )
-    ([[:punct:]]|\s|<|$)    # trailing text
-   ~x');
+    ([^a-zA-Z0-9_\-\/.,:;\~\?@&=+$%#!()]|\ |<|$)    # trailing text
+   ~xu');
 }
 
 function op_url_cmd($text)
diff --git a/test/unit/helper/opUtilHelperTest.php b/test/unit/helper/opUtilHelperTest.php
index ab5aa5a7e..7e2eeeb83 100644
--- a/test/unit/helper/opUtilHelperTest.php
+++ b/test/unit/helper/opUtilHelperTest.php
@@ -75,3 +75,23 @@
 
 Doctrine::getTable('SnsConfig')->set('nickname_of_member_who_does_not_have_credentials', 'I am a pen.');
 $t->is(op_link_to_member(null), 'I am a pen.', 'set nickname_of_member_who_does_not_have_credentials original setting');
+
+//------------------------------------------------------------
+$t->diag('op_auto_link_text()');
+$t->is(op_auto_link_text('http://example.com/'), '<a href="http://example.com/" target="_blank">http://example.com/</a>');
+$t->is(op_auto_link_text('https://example.com/'), '<a href="https://example.com/" target="_blank">https://example.com/</a>', 'protocol');
+$t->is(op_auto_link_text('http://sub.example.com/'), '<a href="http://sub.example.com/" target="_blank">http://sub.example.com/</a>', 'subdomain');
+$t->is(op_auto_link_text('http://example.com/hoge'), '<a href="http://example.com/hoge" target="_blank">http://example.com/hoge</a>', 'path');
+$t->is(op_auto_link_text('http://example.com:8080/'), '<a href="http://example.com:8080/" target="_blank">http://example.com:8080/</a>', 'port');
+$t->is(op_auto_link_text('http://example.com/#foo'), '<a href="http://example.com/#foo" target="_blank">http://example.com/#foo</a>', 'anchor');
+$t->is(op_auto_link_text('http://example.com/?foo=1&bar=0'), '<a href="http://example.com/?foo=1&bar=0" target="_blank">http://example.com/?foo=1&bar=0</a>', 'query');
+$t->is(op_auto_link_text('https://sub.example.com:8080/hoge?foo=1&bar=0#foo'), '<a href="https://sub.example.com:8080/hoge?foo=1&bar=0#foo" target="_blank">https://sub.example.com:8080/hoge?foo=1&bar=0#foo</a>');
+$t->is(op_auto_link_text('http://example.com'), '<a href="http://example.com" target="_blank">http://example.com</a>');
+$t->is(op_auto_link_text('www.example.com'), '<a href="http://www.example.com" target="_blank">www.example.com</a>');
+// see https://trac.openpne.jp/ticket/3553
+$t->is(op_auto_link_text('http://example.com/#comment:1'), '<a href="http://example.com/#comment:1" target="_blank">http://example.com/#comment:1</a>');
+// see https://redmine.openpne.jp/issues/3289
+$t->is(op_auto_link_text('http://example.com/テキスト'), '<a href="http://example.com/" target="_blank">http://example.com/</a>テキスト');
+$t->is(op_auto_link_text('http://example.com/hogeテキスト'), '<a href="http://example.com/hoge" target="_blank">http://example.com/hoge</a>テキスト');
+$t->is(op_auto_link_text('http://example.comテキスト'), '<a href="http://example.com" target="_blank">http://example.com</a>テキスト');
+$t->is(op_auto_link_text('http://example.com:８０８０/'), '<a href="http://example.com:" target="_blank">http://example.com:</a>８０８０/'); // http://example.com:/ is valid URI.