  We analyze the semileptonic rare decays of $B$ meson to $K_{1} (1270)$ and
$K_{1} (1400)$ axial vector mesons. The $B\to K_{1} (1270,1400) \ell^+ \ell^-$
decays are significant flavor changing neutral current decays of the $B$ meson.
These decays are sensitive to the new physics beyond SM, since these processes
are forbidden at tree level at SM. These decays occurring at the quark level
via $b\to s \ell^+ \ell^- $ transition, also provide new opportunities for
calculating the CKM matrix elements $V_{bt}$ and $V_{ts}$. In this study, the
transition form factors of the $B\to K_{1} (1270,1400) \ell^+ \ell^-$ decays
are calculated using three-point QCD sum rules approach. The resulting form
factors are used to estimate the branching fractions of these decays.
