  We investigate the role of magnetic field on the gas dynamics in a galactic
bulge region by three dimensional simulations with radiative cooling and
heating. While high-temperature corona with $T>10^6\ {\rm K}$ is formed in the
halo regions, the temperature near the mid-plane is $\lesssim 10^4\ {\rm K}$
following the thermal equilibrium curve determined by the radiative cooling and
heating. Although the thermal energy of the interstellar gas is lost by
radiative cooling, the saturation level of the magnetic field strength does not
significantly depend on the radiative cooling and heating. The magnetic field
strength is amplified to $10\ {\rm \mu G}$ on average, and reaches several
hundred ${\rm \mu G}$ locally. We find the formation of magnetically dominated
regions at mid-latitudes in the case with the radiative cooling and heating,
which is not seen in the case without radiative effect. The vertical thickness
of the mid-latitude regions is $50-150\ {\rm pc}$ at the radial location of
$0.4-0.8\ {\rm kpc}$ from the galactic center, which is comparable to the
observed vertical distribution of neutral atomic gas. When we take the average
of different components of energy density integrated over the galactic bulge
region, the magnetic energy is comparable to the thermal energy. We conclude
that the magnetic field plays a substantial role in controlling the dynamical
and thermal properties of the galactic bulge region.
