A rotary drive mechanism, which is capable of precisely controlling the rotational angle of an output shaft or a rotor. In the rotary drive system of the present invention, a first moving guide is provided in parallel to first guides, each end section of the first moving guide is movably connected to second guides. A second moving guide is provided in parallel to the second guides, each end section of the second moving guide is movably connected to the first guides. A moving body is capable of moving on the first and the second moving guides. A first motor moves the moving body in the first direction, and a second motor moves the moving body in the second direction. A lever rotates an output shaft when the moving body moves round the output shaft, an outer end section of the lever is rotatably connected to the moving body and capable of moving in the longitudinal direction with respect thereto, an inner end section of the lever is fixed to one end of the lever.