A device for reducing friction while maintaining characteristics identical to the pressure characteristics of a common oil pump based on provision of a plurality of discharge sources and a newly devised method of switching oil passages. The device is configured from a first discharge passage from a first rotor assembly to an engine, a first return passage that returns to an intake side of the first rotor assembly, a second discharge passage from a second rotor assembly to the engine, a second return passage that returns to an intake side of the second rotor assembly, and a pressure control valve whose valve main body is provided between a discharge port from the second rotor assembly and the first discharge passage. The first discharge passage and the second discharge passage are coupled, and a flow passage control is executed in each of: a low revolution range in a state in which only the first discharge passage and the second discharge passage are open; an intermediate revolution range in a state in which the first discharge passage and second discharge passage are open and the first return passage is closed while the second return passage is open; and a high revolution range in a state in which the second discharge passage is closed while the first discharge passage is open and the first return passage and second return passage are open.