A battery module includes a battery assembly having battery structures arranged side by side, the battery structures each having a battery body having a battery cell and a battery holder for holding the battery body, and a pressure application member for applying pressure to the battery assembly in a direction in which the battery structures are arranged side by side. Each battery holder has a first surface intersecting with the arrangement direction of the battery structures, a second surface located on the opposite side to the first surface, a projecting portion, which projects from the first surface in the arrangement direction of the battery structures and has a distal end face, and a receptacle portion recessed in the second surface in the arrangement direction of the battery structures. The projecting portion of each battery holder is inserted into the receptacle portion of the adjacent battery holder in a state in which the distal end face is free of contact with the adjacent battery holder. Each battery body contacts the adjacent battery body such that at least one of the first and second surfaces of the battery holder, which holds a battery body, is free from contact with the adjacent battery holder.
