Provided is a power supply device, provided for a light source device which has a plurality of light-emitting bodies. The power supply device includes a circuit for controlling a current supplied to the light-emitting body. The power supply device also includes a control circuit for controlling a current from a power supply source, the control circuit being disposed at the central portion of the light source device. The power supply device additionally includes a cooling component capable of cooling surroundings by channeling a refrigerant, where the cooling component is provided on a back side of the light-emitting body. The power supply device also includes a heat transfer component connecting the cooling component and the control circuit to each other. The power supply device further includes an insulating component interposed between the heat transfer component and the control circuit at a state in contact with both.