A power supply device includes a circuit board that has an arrangement surface and a rear surface opposite to the arrangement surface and that has a through hole. An insertion mounted circuit component, a connector and a surface mounted light emitting component that is provided for confirming an operation of the power supply device are assembled on the arrangement surface. A chassis holds the circuit board from the sides and the rear surface of the circuit board and has an opening to expose the connector. The surface mounted light emitting component is surface mounted on the rear surface of the circuit board. The through hole is provided near the surface mounted light emitting component so as to guide light emitted from the surface mounted light emitting component toward the opening of the chassis.