  We make a comprehensive study of vector-like fermionic dark matter and flavor
anomalies in a simple extension of standard model. The model is added with
doublet vector-like fermions of quark and lepton types, and also a
$S_1(\bar{\textbf{3}},\textbf{1},1/3)$ scalar leptoquark. An additional lepton
type singlet fermion is included, whose admixture with vector-like lepton
doublet plays the role of dark matter and is examined in relic density and
direct detection perspective. Electroweak precision observables are computed to
put constraint on model parameter space. We constrain the new couplings from
the branching ratios and angular observables associated with $b \to sll (\nu_l
\bar \nu_l)$, $b \to s \gamma$ decays and also from the recent measurement on
muon anomalous magnetic moment. We then estimate the branching ratios of the
rare lepton flavor vioalting $B_{(s)}$ decay modes such as $B_{(s)} \to l_i^\mp
l_j^\pm$, $B_{(s)} \to (K^{(*)}, \phi) l_i^\mp l_j^\pm$.
