In order to allow gas discharged from a pouch cell to be guided to a predetermined position, a power source device includes one or a plurality of pouch cells (10) having laminated film outer casing (11), and a housing member (20) enclosing the one or multiple pouch cells (10). The one or plurality of pouch cells (10) each includes thermally welded portion (13) formed by thermally welding the laminated film, and gas discharge portion (14) provided in at least a part of thermally welded portion (13). Housing member (20) includes exhaust port (22) communicating with gas discharge portion (14) of one or a plurality of pouch cells (10).