In the oil lubrication structure that supplies lubricating oil to the transmission device, the oil lubrication structure includes an oil passage formed above a transmission device. The oil passage is formed by an oil groove portion and a plate member. The oil groove portion is integrally formed in a crankcase. The plate member is arranged in the crankcase so as to cover the oil groove portion. The plate member has oil dripping holes formed therein, and the oil dripping holes are opened at positions directly above the transmission device.