Edit in JSFiddle

    $(document).ready(function(){ 
         $(".toggle_faq").hide();
         $("h3.switch").click(function(){
        $(this).toggleClass("active").next().slideToggle("normal");
        return false;
    });
   }); 

<h3 class="switch faq_head">なんで生きてるの？</h3><div class="toggle_faq faq">別にいいですやん</div><br />
<h3 class="switch faq_head">なぜ地球は丸いの？</h3><div class="toggle_faq faq">丸いからです</div><br />
<h3 class="switch faq_head">今まで何匹のワンコをもふもふしてきたの？</h3><div class="toggle_faq faq">50匹かな</div><br />
<h3 class="switch faq_head">なんで貧乏なの？</h3><div class="toggle_faq faq">しらんがな</div><br />

*{font-family: "メイリオ", "Meiryo", "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "ＭＳ ゴシック", "Osaka", sans-serif ;}
h3.switch {
        font-size: 22px ;
        padding:7px 0 7px 22px ;
        border-left: 3px solid #e91b1b;
        margin: 10px 0;
        color: #282828 ;
    cursor:pointer;
}

h3.active {
    color: red;
}

.toggle_faq {
    overflow: hidden;
    padding: 20px 10px;
}