  We present an analytic model in which an inefficiently radiating accretion
disk drives upward wind from its surfaces. The accretion process is controlled
simultaneously by a global magnetic field penetrating the disk and by a
viscosity of the accreting plasma. It is shown that energy is transported
radially outward within the accreting flow, associated with the viscous
angular-momentum transport in the same direction, and that this addition of
energy from the inner part to the disk part makes the latter possible to drive
an upward wind. The parameter that specifies the strength of a wind is
determined uniquely in terms of a naturally introduced viscosity parameter.
