To provide a power supply controller which automatically switches on and off the power of peripheral equipment associatively with the operation of a computer.

The power supply controller 1 is equipped with an operation detection part 2 which detects the operation of a keyboard, a mouse, etc., an ON/OFF control part 3 which switches ON and OFF the power of the peripheral equipment with the output of the operation detection part 2, and an outlet 4 for the peripheral equipment which is controlled by the ON/OFF control part 3. The electric power is supplied to the outlet 4 by a power cord 5 through the ON/OFF control part. Devices such as the keyboard 6 and mouse 7 are connected to the operation detection part 2 of the power supply controller 1 and these devices are connected to the computer 8 through the power supply controller 1. Further, a printer 9 and a monitor 10 as peripheral equipment are connected to the computer 8 and the power cord 9a of the printer 9 and the power cord 10a of the monitor 10 are connected to the peripheral equipment outlet 4 of the power supply controller 1 and the electric power is supplied from the power supply controller 1.