A battery module is provided whereby loss of productivity can be minimized even when producing multiple exterior body parts for different battery module sizes. The battery module of the disclosure has an exterior body and an all-solid-state battery stack encapsulated in the exterior body. The exterior body has a tubular body and a pair of covers. The tubular body has flanges at both open ends. The flanges at both ends of the tubular body and the outer edge sections of the pair of covers are each joined forming joints, with the exterior body being sealed by the joints. The all-solid-state battery stack has one or multiple constituent unit cells. The direction of stacking of each of the layers of the constituent unit cell is in the axial direction of the tubular body.