A power supply device including a casing and a power supply module is provided. The casing has an opening. The power supply module includes a frame, a pin base, a plurality of pins and a printed circuit board. The frame is detachably disposed in the casing. The pin base is fixed at the frame and is exposed by the opening. The pins are fixed at the pin base, and first ends of the pins are exposed in the opening. The printed circuit board is disposed in the casing and is electrically connected to second ends of the pins.