Abstract: A plugtype power supply unit includes an enclosure, a plug portion secured thereto, and a low-voltage cord extending from said enclosure. Each cross-sectional configuration of said enclosure with said plug portion corresponds to and does not exceed the cross-sectional configuration of a plug face of an American type plug according to the NEMA 1-15P standard. A switch mode power supply circuit mounted on a PCB is built into said enclosure, said switch mode power supply circuit includes a transformer for power converting and a capacitor for regulating an input voltage, a central axis of said capacitor is disposed parallel to the direction of said PCB.