A battery module includes a box-shaped housing case that is open at an upper side and that does not include a hole formed in a side wall, a battery stack that includes plural battery cells stacked along a horizontal direction and that is housed inside the housing case, and a shim that is disposed between the battery stack and the housing case so as to press the battery stack along the stacking direction of the battery cells in a state in which the battery stack is housed inside the housing case.