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   81411
   In the Galactic Center survey, ASCA resolved many point sources in the
   region through the heavy interstellar absorption for the first time.
   Some of them were found to show unusually hard spectra. They are
   probably one of unusual objects, such as X-ray pulsar or black hole. In
   particular, one of the targets, AX J1739.1-3021, showed an extremely
   strong flare with more than 2-order magnitude variability in only
   1000sec. We here propose the long observations of three of those
   unusually hard objects which have been not identified, yet. Our first
   objective is to detect time variability and then to reveal their
   natures. In addition to the interest to their natures themselves, they
   would give some important implication on the star formation history in
   the Galactic Center region.
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