An end plate has a recess extending in the horizontal direction and configured to form a flow path in which cooling water flows. Ribs are formed on the bottom surface of the recess and arranged at intervals in the vertical direction so as to extend in the horizontal direction. The cooling water flows in from the passage of a cell stack at one end in the horizontal direction of the recess. A hole that allows the cooling water to flow out is provided at the other end and at a position higher than the portion into which the cooling water flows. The inner wall surfaces of the recess spread vertically toward the hole in the portion connected to the passage. The end close to the passage of the lowermost one of the ribs is closer to the hole than the ends close to the passage of the other ribs.