A merge and discharge unit (7) has: a reservoir unit (14) in which fuel can be collected; a first merge unit (15) for merging into the reservoir unit the fuel from an upstream site upstream of the merge and discharge unit on a fuel supply route; a second merge unit (16) for merging into the reservoir unit (14) the fuel from a first fuel return route (12); a first discharge unit (17) for discharging a portion of the fuel of the reservoir unit into a downstream site downstream of the merge and discharge unit (18) on the fuel supply route; and a second discharge unit for discharging a remaining portion of the fuel of the reservoir unit (14) into a second fuel return route (13).
