A battery is provided with a battery stack body including a plurality of stacks of secondary batteries in each of which electrode plates, stacked via a separator, are accommodated and sealed in an outer sheath member, with electrode terminals correspondingly connected to the electrode plates and extracted from an outer peripheral edge of the outer sheath member, a pair of plate-like members, stacked as outermost layers of the battery stack body, respectively, so as to be opposed to each other, and a pressing mechanism pressing the plurality of secondary batteries via the pair of plate-like members. At least one of the pair of plate-like members having a characteristic exhibiting a maximum rigidity at a pressing center determined based on a plurality of pressing points of the at least one of the pair of plate-like members that are pressed by the pressing mechanism.