To provide a wind power generation device having reduced manufacturing cost by using an inexpensive actuator for turning a nacelle.

The wind power generation device comprises a windmill, a generator connected to the main shaft of the windmill, the nacelle for storing the generator, etc., and a tower for turnably supporting the nacelle. It has a hydraulic cylinder 13 for varying the pitch angle of each blade of the windmill, and a hydraulic motor 15 for varying the turning position of the nacelle. Pressure oil is supplied to the hydraulic cylinder and the hydraulic motor to be driven via selector valves 33, 37, respectively.