PURPOSE: To enable unmanned automatic operation of a system, by interpreting a information of power supply application from a CPU, applying the power supply to an auxiliary equipment, a power supply controller and a processing system, and making the system operating state.

CONSTITUTION: An automatic power supply application device 8 is connected to an input and output processing device 3 with a data control interface (shown in solid lines) the same as an external storage subsystem 4 and an input and output subsystem 5, and to a power supply controller 7 with a power supply applying control interface (shown in double dotted lines). The power supply applying information received in advance from a CPU1 is interpreted and stored to output a power supply applying signal to an additional equipment at a specified time and to the power supply controller 7 next, and a start information enabling to operate a processing system 6 is transmitted to the CPU via a system control interface (shown in double solid lines) to perform the unmanned automatic operation of the system.