  We investigate the hybrid exotic meson with $J^{PC}=1^{-+}$ within the
framework of an AdS/QCD model. Introducing a holographic field dual to the
operator for hybrid exotic meson, we obtain the eigen-value equation for its
mass. Fixing all free parameters by QCD observables such as the $\rho$-meson
mass, we predict the masses of the hybrid exotic meson. The results turn out to
be $1476 \mathrm{MeV}$ for the ground state, and $2611 \mathrm{MeV}$ for the
first excited one. Being compared with the existing experimental data for the
$\pi_1(1400)$, which is known to be $m_{\pi_1} = 1351\pm30 \mathrm{MeV}$, the
present result seems to be qualitative in agreement with it. We also predict
the decay constant of $\pi_1$(1400): $F_{\pi_1}= 10.6$ MeV.
