A battery module includes: a cell stack body that is constituted by a plurality of cells stacked in a front-rear direction; a pair of end plates disposed on a front surface and rear surface of the cell stack body; and a pair of side frames disposed on the left surface and right surface of the cell stack body. The end plates each includes: an inner wall extending along the cell stack body; an outer wall spaced from the inner wall and facing the inner wall; a plurality of connection walls connecting the inner wall and the outer wall with each other; and a plurality of hollow portions formed by the inner wall, the outer wall, and the connection walls and extending in an up-down direction. A thickness of the connection walls is thinner than a thickness of the inner wall.