$re = '/(?<![\u4E00-\u9FAF\u3040-\u3096\u30A1-\u30FA\uFF66-\uFF9D\u31F0-\u31FF])(?<!\d)(?<!\d\.)(\d+(?:\.\d+)?m2)/m';
$str = '"110.94m2・129.24m2";
--> 110.94m2 and 129.24m2
"81.95m2(24.78坪)、うち2階車庫8.9m2"
--> 81.95m2
"80.93m2(登記)"
--> 80.93m2
"93.42m2・93.85m2(登記)"
--> 93.42m2 and 93.85m2
"81.82m2(実測)"
--> 81.82m2
"81.82m2(実測)、うち1階車庫7.82m2"
--> 81.82m2
"90.11m2(実測)、うち1階車庫8.07m2"
--> 90.11m2';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php