<h1 class="cp_h1title">見出しテキスト</h1>

.cp_h1title {
  position: relative;
  color:#ffffff;
  background: #AB47BC;
  text-align: center;
  padding: 0 70px;
  overflow: hidden;/*はみ出さないように設定*/
}
.cp_h1title:before,
.cp_h1title:after {
  content: '';
  position: absolute;
  top: -10px;
  display: block;
  width: 1px;/*線の太さ*/
  height: 130%;
  background-color: #ffffff;/*線の色*/
  transform: rotate(-25deg);/*線の角度*/
}
.cp_h1title:before {
  left: 30px;
}
.cp_h1title:after {
  right: 30px;
}