Edit in JSFiddle

moment.locale('ja');

var now = moment().format('YYYY-MM-DD HH:mm:ss');

console.log(now);

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.10.6/moment.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.10.6/locale/ja.js"></script>