In a docking station for a PC, a PCI adapter, an IDE controller, and a PC card controller operate when a PCI clock is supplied from the PC, and stop when the supply of the PCI clock is stopped by the PC entering a sleep mode. A driving signal output circuit outputs an actuation signal to a cooling fan drive circuit when the PCI clock is supplied thereto, and outputs a stop signal to the cooling fan drive circuit when the supply of the PCI clock is stopped. The cooling fan drive circuit includes a temperature sensor for detecting the internal temperature of a power supply unit, and controls on/off of the cooling fan on the basis of the detected temperature by this temperature sensor and an output signal from the driving signal output circuit.