  We studied the feasibility of measurement of Higgs pair creation in a gamma
gamma collider. We found the optimum collision energy is around 270 GeV from
the sensitivity study with Higgs boson mass of 120 GeV/c^2. Main backgrounds
are gamma gamma to WW, gamma gamma to ZZ, and gamma gamma to bbbb at the
optimum collision energy. The preliminary analysis shows HH could be observed
with the statistical significance of about 5 sigma when we chose correct
assignment of a track by using color singlet information.
