  In this paper we study the semileptonic decays of $B^\ast$, $B_s^\ast$, and
$B_c^\ast$ by using the Bethe-Salpeter method with instantaneous approximation.
Both the $V\to Pl^-\bar\nu_l$ and $V\to Vl^-\bar\nu_l$ cases are considered.
The largest partial width of these channels is of the order of $10^{-14}$ GeV.
The branching ratios of these semileptonic decays are also estimated by using
the partial width of the one photon decay channel to approximate the total
width. For $B^{\ast-}\to D^{(\ast)0}e^-\bar\nu_e$ and $B_s^{\ast0}\to
D_s^{(\ast)+}e^-\bar\nu_e$, the branching ratios are of the order of $10^{-8}$
and $10^{-7}$, respectively. For $B_c^{\ast-}$, the $J/\psi e^-\bar\nu_e$ and
$B_s^{\ast0}e^-\bar\nu_e$ channels have the largest branching ratio, which is
of the order of $10^{-6}$.
