A wind power generator comprises a first power generator including a rotor arranged so as to be coaxial with a rotation shaft and generates electric power by the rotation of the rotor, a flywheel which is coaxial with the rotation shaft and arranged through a one-way clutch so that when the rotation shaft increases its speed, the flywheel is in an integrally rotating state with the rotation shaft, and when the rotation shaft reduces its speed, the flywheel is separated from the rotation shaft to rotate inertially, a second power generator including a rotor arranged so as to be coaxial with the flywheel and rotate integrally with the flywheel generates the electric power by the rotation of the rotor with the rotation of the flywheel, and an output portion which externally outputs any one of the electric powers generated by the first and second power generators.