Edit in JSFiddle

<body>
    <form>
        <input class="button" type="submit" value="送信"/>
        <a class="button" href="#">ボタン</a>
    </form>
</body>

* {
    font-size: 100%;
    font: inherit;
}
input[type=submit].button {
  color: #FFF;
  background: #FF7F00;
  border: 0;
  font-size: 150%;
  padding: 3px 45px;
}

a.button {
  text-decoration: none;
  color: #FFF;
  background: #FF7F00;
  font-size: 150%;
  margin: 0;
  border: 0;
  padding: 3px 45px;
  display: inline-block;
  line-height: inherit;
}