  In this work, we calculate the rare decays $B^0 \to D_s^{*-} K^+$ and $B^+
\to D_s^{*+} \bar{K}^0$ in perturbative QCD approach with Sudakov resummation.
We give the branching ratio of $10^{-5}$ for $B^0 \to D_s^{*-}K^+$, which will
be tested soon in $B$ factories.
  The decay $B^+ \to D_s^{*+} \bar{K}^0$ has a very small branching ratio at
${\cal O}(10^{-8})$, due to the suppression from CKM matrix elements $|V_{ub}^*
V_{cd}|$. It may be sensitive to new physics contributions.
