  We numerically study the superradiant instability of charged massless scalar
field in the background of charged stringy black hole with mirror-like boundary
condition. We compare the numerical result with the previous analytical result
and show the dependencies of this instability upon various parameters of black
hole charge $Q$, scalar field charge $q$, and mirror radius $r_m$. Especially,
we have observed that imaginary part of BQN frequencies grows with the scalar
field charge $q$ rapidly.
