A first chain mechanism for transmitting the rotation of a crankshaft of an vertical engine to a camshaft and a second chain mechanism for transmitting the rotation of the crankshaft to a balancer shaft are forcibly lubricated by an oil injected by first, second and third oil jets mounted within a chain chamber. The first, second and third oil jets are disposed at locations closer to the crankshaft, the cam shaft and the balancer shaft, respectively, and the first and second oil jets are disposed inside a travel locus for a timing chain. Thus, the chain mechanisms disposed in a plane of the vertical engine can be lubricated effectively.