  We examined the effect of toroidal magnetic fields on a viscous gaseous disk
around a central object under an advection dominated stage. We found
self-similar solutions for radial infall velocity, rotation velocity, sound
speed, with additional parameter $\beta$ [$=c_{\rm A}^2/(2c_{\rm s}^2)$], where
$c_{\rm A}$ is the Alfv\'en speed and $c_{\rm s}$ is the isothermal sound
speed. Compared with the non-magnetic case, in general the disk becomes thick
due to the magnetic pressure, and the radial infall velocity and rotation
velocity become fast. In a particular case, where the magnetic field is
dominant, on the other hand, the disk becomes to be magnetically supported, and
the nature of the disk is significantly different from that of the weakly
magnetized case.
