A group of IT devices is divided into zones according to a predetermined condition. An IT managing server that manages the group of IT devices sends a control request for changing the state of IT devices included in one of the zones according to the state of those IT devices under its management. The control request specifies the zone as a control target. A facility managing server that manages a group of facility devices receives the control request and controls a facility device that exerts effect on the zone, which is specified as the control target in the control request.