  We study an extended Standard Model with a gauged U(1)$^{\prime}$ flavor
symmetry, motivated not only by the fermion mass hierarchy but also by the
excesses in $B \to K^{(*)} l l$ reported by the LHCb collaborations. The
U(1)$^{\prime}$ charges are assigned to quarks and leptons in a
flavor-dependent manner, and flavored Higgs doublets are also introduced in
order to detail the Yukawa couplings at the renormalizable level. Then, the
fermion mass hierarchy is realized by the vacuum alignment of the Higgs
doublets. In this model, flavor-changing currents involving the gauge boson of
U(1)$^{\prime}$ and the scalars generated by the Higgs doublets are predicted
and the observables in the $B \to K^{(*)} l l$ process possibly deviate from
the Standard Model predictions. We study the possibility that these new
flavor-changing interactions can explain the excesses in the $B \to K^{(*)} l
l$ process, and we derive some predictions for the other flavor-violating
processes based on the analysis. We specifically investigate the $\Delta F=2$
processes and the other $B$ decays: e.g., $B \to X_s \gamma$ and $B \to D^{(*)}
\tau \nu$, where the deviations are reported by the Belle and $BABAR$
collaborations.
