function Random() {
     var kazu = Math.random();
     kazu = kazu*3;
     kazu = Math.ceil(kazu);

     if( kazu<=1 )
document.write('<div id="head_banner"><a href="http://www.redbaron.co.jp/license/index.html?utm_source=sbana&utm_medium=license&utm_campaign=roll1" target="_blank"><img src="http://www.redbaron-parts.jp/assets_c/2010/04/head_banner-thumb-567xauto-29.gif" /></a></div>');
     else if( kazu<=2 )
document.write('<div id="head_banner"><a href="http://www.redbaron.co.jp/press/entrys/01/3564.html" target="_blank"><img src="http://www.redbaron-parts.jp/assets_c/2010/04/hyosung_super-thumb-567xauto-27.jpg" /></a></div>');
     else if( kazu<=3 )
document.write('<div id="head_banner"><a href="http://www.redbaron.co.jp/sell/direct.html?utm_source=sbana&utm_medium=sell&utm_campaign=roll1" target="_blank"><img src="http://www.redbaron-parts.jp/assets_c/2010/04/direct_sbanner-thumb-567xauto-26.gif" /></a></div>');
     
   }
  Random()