  We study the effect of the FCNC on rare $B$ decays in the beyond standard
model with vector like singlet quarks. It has been shown that $b \rightarrow s
\gamma $ does not receive sizable contribution compared with that of the
standard model while $b \rightarrow d \gamma $, $b \rightarrow s(d) l^+ l^-$,
can be changed from the predictions of the standard model.
