A power supply device includes a first conversion module and a second conversion module. The first conversion module is adapted to convert a first alternating current into a first direct current and includes a first body, a first input portion having a first alternating current input terminal, a first output portion having a first output terminal, and a first coupling portion having a first coupling terminal. The first coupling terminal and the first output terminal are connected. The second conversion module is adapted to convert a second alternating current into a second direct current and includes a second body, a second input portion having a second alternating current input terminal, a second coupling portion having a second coupling terminal, a third coupling portion having a third coupling terminal, and a second output portion having a second output terminal. The second output terminal and the second coupling terminal are connected.