A battery module comprising: a plurality of battery cells arranged side by side in a first direction, each of the plurality of battery cells having a prismatic shape; an end plate provided to be arranged side by side with the plurality of battery cells in the first direction; and a restraint member that restrains the plurality of battery cells and the end plate along the first direction, the restraint member being provided to be arranged side by side with the plurality of battery cells and the end plate in a second direction orthogonal to the first direction, wherein the end plate includes a plate-shaped member (100, 200), the plate-shaped member (100, 200) includes a flat surface portion (150, 230) extending orthogonally to the first direction, a flange portion (140, 220), and a transition portion (160, 240), the flange portion (140, 220) being provided at an end portion of the plate-shaped member (100, 200) in a third direction orthogonal to the first direction and the second direction, the flange portion (140, 220) protruding from the flat surface portion (150, 230) in the first direction, the transition portion (160, 240) continuously transitioning with a continuous curved surface that has no angular portion from the flat surface portion (150, 230) to the flange portion (140, 220), the plate-shaped member (100, 200) has a wave shape including a protrusion and a recess each extending in the second direction, the flat surface portion (150, 230) is provided to be located at the recess, the flange portion (140, 220) is not provided at both end portions of the end plate in the second direction, the flat surface portion (150, 230) extends to a tip in the third direction of the plate-shaped member (100, 200), and the flat surface portion (150, 230), the transition portion (160, 240), and the flange portion (140, 220) are provided to be arranged side by side in the second direction. a plurality of battery cells arranged side by side in a first direction, each of the plurality of battery cells having a prismatic shape; an end plate provided to be arranged side by side with the plurality of battery cells in the first direction; and a restraint member that restrains the plurality of battery cells and the end plate along the first direction, the restraint member being provided to be arranged side by side with the plurality of battery cells and the end plate in a second direction orthogonal to the first direction, wherein the end plate includes a plate-shaped member (100, 200), the plate-shaped member (100, 200) includes a flat surface portion (150, 230) extending orthogonally to the first direction, a flange portion (140, 220), and a transition portion (160, 240), the flange portion (140, 220) being provided at an end portion of the plate-shaped member (100, 200) in a third direction orthogonal to the first direction and the second direction, the flange portion (140, 220) protruding from the flat surface portion (150, 230) in the first direction, the transition portion (160, 240) continuously transitioning with a continuous curved surface that has no angular portion from the flat surface portion (150, 230) to the flange portion (140, 220), the plate-shaped member (100, 200) has a wave shape including a protrusion and a recess each extending in the second direction, the flat surface portion (150, 230) is provided to be located at the recess, the flange portion (140, 220) is not provided at both end portions of the end plate in the second direction, the flat surface portion (150, 230) extends to a tip in the third direction of the plate-shaped member (100, 200), and the flat surface portion (150, 230), the transition portion (160, 240), and the flange portion (140, 220) are provided to be arranged side by side in the second direction.