  The Time Projection Chamber (TPC) has been recognized as a potentially
powerful detector for the search of WIMPs by measuring the directions of
nuclear recoils, in which the most convincing signature of WIMPs, caused by the
Earth's motion around the Galaxy, appears.
  We report on the first results of a performance study of the neutron exposure
of our prototype micro-TPC with Ar-C$_2$H$_6$ (90:10) and CF$_4$ gas of 150
Torr.
