  We report on our study of two-flavor full QCD on anisotropic lattices using
$O(a)$-improved Wilson quarks coupled with an RG-improved glue. The bare gauge
and quark anisotropies corresponding to the renormalized anisotropy
$\xi=a_s/a_t = 2$ are determined as functions of $\beta$ and $\kappa$, which
covers the region of spatial lattice spacings $a_s\approx 0.28$--0.16 fm and
$m_{PS}/m_V\approx 0.6$--0.9. The calibrations of the bare anisotropies are
performed with the Wilson loop and the meson dispersion relation at 4 lattice
cutoffs and 5--6 quark masses. Using the calibration results we calculate the
meson mass spectrum and the Sommer scale $r_0$. We confirm that the values of
$r_0$ calculated for the calibration using pseudo scalar and vector meson
energy momentum dispersion relation coincide in the continuum limit within
errors. This work serves to lay ground toward studies of heavy quark systems
and thermodynamics of QCD including the extraction of the equation of state in
the continuum limit using Wilson-type quark actions.
