A wind power generator includes: an input rotor provided so as to be rotatable together with an output shaft of a speed increaser; an output rotor provided so as to be rotatable together with a drive shaft of a generator; and a one-way clutch arranged between the input and output rotors. The one-way clutch connects the input rotor to the output rotor such that the input rotor and the output rotor are rotatable together with each other when a rotation speed of the input rotor exceeds a rotation speed of the output rotor, and that disconnects the input rotor from the output rotor when the rotation speed of the input rotor falls below the rotation speed of the output rotor. The one-way clutch has a rotation speed limiter that disconnects the input rotor from the output rotor when the rotation speed of the output shaft exceeds a predetermined value.