  The short distance QCD corrections to $b\to s\gamma \gamma$ are calculated in
the leading logarithmic approximation. The equivalence of operator basis
reduction for S-matrix elements by using the equations of motion or by proving
a low energy theorem is discussed. We apply the above results to the exclusive
$B_s\to \gamma\gamma$ decay. The branching ratio of this decay is found to be
$5\times 10^{-7}$ in the Standard Model. We also found that QCD corrections
modify considerably the ratio between CP-even and CP-odd two-photon amplitudes.
