To provide a drive device with the through-put free of lowering and embodied in a less large construction.

A supporting mechanism to transmit the power of a motor 103 as a drive source to a mechanism part 106 as a member to be driven through a rotary shaft 10 and support the rotary shaft 10 is equipped with a functional fluid with the viscosity variable and a viscosity controlling means to control the viscosity of the functional fluid. The viscosity controlling means controls when the motor 103 is in operation so that the viscosity of the functional fluid lowers, and when the motor 103 is at a standstill, controls so that the viscosity of the functional fluid heightens.