  Including corrections of order $O(m_{K^*}/m_B)$, we present an analysis of
photonic penguin contributions to the decay $B\to K^* \gamma$ in the
perturbative QCD framework. Employing several models of the meson wave
functions, we demonstrate that the corrections of $O(m_{K^*}/m_B)$ are enhanced
and will providesubstantial contributions to the decay because of the B meson
wave function being sharply peaked (bound state effect). The numerical
predictions for the corrections are about $30%\sim 60%$ which depend on the
non-perturbative inputs such as the meson wave functions and the $b$-quark
mass.
