Edit in JSFiddle

#esnekKutuKapsul{
  display: box;
  display:-webkit-box;
  display:-moz-box;
  width:600px;
  border:1px solid #03C;
  box-pack:center;
  -webkit-box-pack:center;
  -moz-box-pack:center;
}

.esnekKutu{
  background-color:#999999;
  width:150px;
  height:150px;
  margin-right:15px;
}
<div id="esnekKutuKapsul">
    <div class="esnekKutu">Esnek Kutu1</div>
    <div class="esnekKutu">Esnek Kutu2</div>
    <div class="esnekKutu">Esnek Kutu3</div>
</div>