Edit in JSFiddle

	<div class="container">
    <div class="middle box">お問い合わせはこちらから</div>
  </div>

body { font-size: 18px; line-height: 1.3; }
.container { padding: 3em; }
.container:after { clear: left; content: ""; display: block; }
.box { background: #fff; border: #d8d8d8 1px solid; box-sizing: border-box; float: left; padding: 1em; text-align: center; }
.middle { width: 200px; margin-right: 20px; }