PURPOSE: To improve the reliability of a system by limiting power supply controlling functions by a service processor only to the control related to the disconnection of an individual power supply.

CONSTITUTION: An operation part 10 controls power supply parts 16, 17 collectively through a system power supply control part 13 and power supply control parts 14, 15 respectively to turn on/off logical devices 11, 12 collectively. In order to turn off the power supply part 17 supplying DC power to the logical device 12 after turning on power sources collectively, a control signal for disconnection is sent from a service processor 9 to the power supply control part 15 through the logical device 12 to turn off the power supply part 17. Therefore, the service processor 9 controls the logical devices 11, 12 and the power supply parts 16, 17 through the power supply control parts 14, 15 corresponding to the logical devices 11, 12 by limiting only to the control of disconnection of an individual power supply. Respective devices 9, 11, 12 are provided with interface apparatuses 9-1, 11-1W11-2 for power supply control.