Provided is a power source module which includes: a plurality of energy storage devices stacked in a stacking direction; end plates sandwiching the plurality of energy storage devices therebetween; and a plurality of fastening bars connecting the end plates to each other; wherein the energy storage device includes: a terminal surface on which an electrode terminal is mounted; a bottom surface; and first and second side surfaces. Each of the fastening bars includes an extending portion extending parallel to the stacking direction and fastening portions extending parallel to the end plates. As viewed in the stacking direction, a total area of the fastening portions positioned in a region close to the terminal surface with respect to a center line between the terminal surface and the bottom surface is set larger than a total area of the fastening portions positioned in a region close to the bottom surface with respect to the center line.