POWER SUPPLY DEVICE, VEHICLE HAVING POWER SUPPLY DEVICE, AND POWER STORAGE DEVICE

In order to improve stiffness of a fastening member, power supply device (100) includes: a pair of end plates (20) disposed on both ends in a stacking direction of battery stack (10) constituted by stacking a plurality of secondary battery cells (1); and a plurality of fastening members (15) fastening the pair of end plates (20) together. Each of fastening members (15) includes fastening main face (15a) having a flat plate shape and locking block (15b) fixed to a corner of fastening main face (15a) Each of end plates (20) is formed with step (20b) that locks locking block (15b) while being fastened by fastening members (15), and has end plate screw hole (20c) opened near step (20b). Each of fastening members (15) has fastening side through hole (15bc) opened so as to align with end plate screw hole (20c) while having each of end plates (20) fastened, and has a fixing region fixing locking block (15b) to fastening main face (15a) disposed in a direction further away from each of end plates (20) than fastening side through hole (15bc).