A battery module has a plurality of prismatic batteries (2) stacked in a thickness direction. Two plates (3, 4) are provided between each of the batteries (2), and each of the batteries (2) is compressed by shifting the two plates (3, 4) in directions away from each other. A pair of frame members (10, 20) having opposing surfaces (11, 21) extending along the stacking direction of the batteries (2) are disposed face to face so as to sandwich the batteries (2) in a direction perpendicular to the stacking direction of the batteries. Wedge-shaped spacers (12, 22) inserted between the two plates (3, 4) are provided respectively on the opposing surfaces. By narrowing the gap between the pair of frame members (10, 20), the spacers (12, 22) are allowed to advance inwardly between the two plates (3, 4) so that the two plates are shifted in directions away from each other, whereby the batteries are compressed.