.top_menu {
}
<table width="800" border="0" cellspacing="1">
  <tr class="top_menu">
    <th scope="col"><div align="center"><a href="location.html"><img src="img/top_menu01a.gif" alt="Ûš°ŧŽŨŒđ’ĘˆÄ“ā" width="110" height="46" border="0" onMouseOver="chg_image(3,'img/top_menu01b.gif')" onMouseOut="chg_image(3,'img/top_menu01a.gif')"/></a></div></th>
    <th scope="col"><div align="center"><a href="sangyo.html"><img src="img/top_menu02a.gif" alt="ŽY‹ÆƒCƒ“ƒtƒ‰" width="110" height="46" border="0" onMouseOver="chg_image(4,'img/top_menu02b.gif')" onMouseOut="chg_image(4,'img/top_menu02a.gif')"/></a></div></th>
    <th scope="col"><div align="center"><a href="kankyo.html"><img src="img/top_menu03a.gif" alt="ËŪŧŪČŊ•ļŠˆŠÂ‹Ģ" width="110" height="46" border="0" onMouseOver="chg_image(5,'img/top_menu03b.gif')" onMouseOut="chg_image(5,'img/top_menu03a.gif')"/></a></div></th>
    <th scope="col"><div align="center"><a href="jinzai.html"><img src="img/top_menu04a.gif" alt="lŪ•‹ŗˆį‹@ŠÖ" width="110" height="46" border="0" onMouseOver="chg_image(6,'img/top_menu04b.gif')" onMouseOut="chg_image(6,'img/top_menu04a.gif')"/></a></div></th>
    <th scope="col"><div align="center"><a href="kaihatu.html"><img src="img/top_menu05a.gif" alt="ŠJ”­Œv‰æ•—§’nķ‹ĩ" width="110" height="46" border="0" onMouseOver="chg_image(7,'img/top_menu05b.gif')" onMouseOut="chg_image(7,'img/top_menu05a.gif')"/></a></div></th>
    <th scope="col"><div align="center"><a href="bunjyo.html"><img src="img/top_menu06a.gif" alt="•Ē÷ˆÄ“ā" width="110" height="46" border="0" onMouseOver="chg_image(8,'img/top_menu06b.gif')" onMouseOut="chg_image(8,'img/top_menu06a.gif')"/></a></div></th>
    <th scope="col"><div align="center"><a href="seido.html"><img src="img/top_menu07a.gif" alt="—D‹ö§“x" width="110" height="46" border="0" onMouseOver="chg_image(9,'img/top_menu07b.gif')" onMouseOut="chg_image(9,'img/top_menu07a.gif')"/></a></div></th>
  </tr>
</table>