There is provided a lubricating structure of a one-way clutch which can lubricate rollers without degrading durability. A direction in which a lubricating oil passage for supplying oil to rollers of the one-way clutch extends is tilted relative to the rotational axis of an inner race and tilted relative to respective rotational axes of the rollers as viewed from the outer circumferential side of the inner race. Thus, a thin-walled part formed between the lubricating oil passage formed just below the roller and the surface on which the rollers roll can be reduced in size. As a result, when the inner race and the outer race are locked, roller's stress is less prone to be concentrated around the thin-walled part, and the deformation of the thin-walled part can be prevented, and therefore the degradation of the durability of the one-way clutch can be prevented.