A chain transmission is provided which is capable of reducing friction loss in the transmission of power without the risk of compromising the durability of a chain guide mechanism and the chain. The chain transmission includes a chain and a chain guide mechanism. The chain guide mechanism includes a first guide and a second guide having a smaller radius of curvature than that of the first guide. The plurality of plates include a first plate and a second plate. The first plate has a backside height set such that the first plate does not contact the first guide when the first plate is guided by the first guide and such that the first plate contacts the second guide when the first plate is guided by the second guide.