A one-way clutch is arranged between an output shaft of a speed increaser and a drive shaft of a generator in a wind power generator. The one-way clutch includes an inner ring, an outer ring, a plurality of rollers arranged between an outer periphery of the inner ring and an inner periphery of the outer ring, a cage that retains the rollers at predetermined intervals in a circumferential direction, and a plurality of elastic members that is attached to the cage and that urges the corresponding rollers in one direction. The cage includes a pair of axially facing annular portions and a plurality of cage bar portions formed separately from the annular portions, both axial end portions of each of the cage bar portions being fitted to the respective annular portions.