A high-pressure return passage returns excess fuel in a delivery pipe that is connected to an injector to a fuel tank. An upstream end of the high-pressure return passage is connected to the delivery pipe via a high-pressure regulator. A vertically lower portion of the high-pressure return passage is vertically below the upstream end and the downstream end. A low-pressure return passage returns excess fuel in a main passage to the fuel tank. The switch valve switches the open state and the closed state of the low-pressure return passage. A control section controls the switch valve to the closed state after the engine is stopped and drives the fuel pump so as to execute a forced return process that flows fuel into the high-pressure return passage.