NOVELTY - The device has a screw mechanism (6) for fixing an end plate (5) of an outer side to a surrounding wall (30). A pressurization block (7) moves a penetration part (33) of an opposing wall (31) along pressurizing direction of a battery block (2). An outside end plate is moved along direction to approach the surrounding wall by the screw mechanism fixed to the opposing wall to pressurize an inside end plate (4A) along lamination direction of the battery block. The inside end plate is fixed to the battery block in an outer case (3) through the pressurization block at a pressurized state.    USE - Power supply device for facilitating electrical storage in a vehicle (claimed) e.g. electric vehicle and plugin type hybrid electric vehicle. Can also be used as a backup power supply apparatus for a wireless base station, computer server, mobile telephone, home internal unit, electrical storage for factories, street light and a solar cell.    ADVANTAGE - The device allows the pressurization block to be provided in the inside end plate and the outside end plate in an simpler and easier manner, so that the pressurization block is provided in an exact position between the inside end plate and the outside end plate to pressurize the battery block, thus reinforcing the inside end plate with the pressurization block, and hence pressing the battery block by stably uniform pressure. The device allows the outside end plate to approach the opposing wall, so that the device is screwing in a stopper screw to fix the battery block to a pressurized state in an easy manner. The device allows surrounding walls to be made from aluminum, so that an outer case can be made with a simple and stronger structure. The device can obstruct an upper opening part of the surrounding wall in a watertight structure by a top cover, thus preventing dew condensation and earth leakage.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded perspective view of a power supply device.'(Drawing includes non-English language text)'    Battery block (2)    Outer case (3)    Inside end plate (4A)    End plate (5)    Screw mechanism (6)    Pressurization block (7)    Surrounding wall (30)    Opposing wall (31)    Penetration part (33)