A power storage device includes a plurality of power storage cells (29), and a heat exchange plate (32) disposed between the plurality of power storage cells (29) so as to face respective long side surfaces of the plurality of power storage cells (29) and extending in a long-side direction of the long side surface. In the heat exchanger (32), Young's modulus of a central portion (32c) in a short-side direction of the long side surface is smaller than Young's modulus of an end portion (32b, 32d) in the short-side direction of the long side surface.
