Abstract: A suction inlet port (48) is formed in an inner peripheral surface on a bottom portion side of a differential housing (15), and the suction inlet port (48) is connected to a suction outlet port (42) formed in an outer peripheral surface of the differential housing (15) via a suction pipe line (43). The suction outlet port (42) is formed in a mounting seat (16) to which a lubricating pump (30) is attached. A discharge port (44) introducing lubricating oil discharged from the lubricating pump (30) is formed in an upper position of the mounting seat (16), and a discharge pipe line 45 is connected to the discharge port (44). Each of a first discharge port (46) and a second discharge port (47) is formed in an end portion of the discharge pipe line (45). The suction pipe line (43) and the discharge pipe line (45) are formed integrally with the differential housing (15) by casting or the like.