This invention provides a lubricating system for a gear train including: a lubricating oil supply port configured to supply a lubricating oil in a direction vertical to both axes of a pair of gears and toward a mesh point at which the pair of gears are meshed with each other; a shroud configured to cover at least teeth of the pair of gears so as to form a flow passage of the lubricating oil between the pair of gears and the shroud; and a pair of discharge ports respectively configured to discharge the lubricating oil from the flow passage. The pair of discharge ports are respectively positioned at two portions of the shroud respectively opposed to the mesh point across respective axes of the pair of gears.