A power storage device includes a case in which at least one unit cell is housed; a heat exchanger (31) that is provided in a wall surface of the case so as to face both an inside of the case and an outside of the case, and that performs heat exchange between the inside of the case and the outside of the case; and a plurality of dividing members (21, 22) that are arranged in an up-down direction inside the case so as to be opened and closed independently of one another, and that divide a space inside the case into a space in which the at least one unit cell is housed and a space in which the heat exchanger is arranged.