A power supply device is provided. The power supply device includes a fuel cell, a hydrogen generator, a check valve and an exhaust valve. The fuel cell has a hydrogen inlet and a hydrogen outlet. The hydrogen generator is connected to the hydrogen inlet and used for generating hydrogen. The check valve is disposed in the hydrogen inlet and used for preventing the hydrogen within the fuel cell from flowing to the hydrogen generator, and preventing exterior air from entering the fuel cell. The exhaust valve is disposed in the hydrogen outlet for exhausting the hydrogen within the fuel cell.