The present invention has an object of realizing a power source redundancy of each of devices constructing a network while suppressing a processing load of each device with a simplified configuration. A power monitoring device includes a power configuration generator for preparing power control information based upon device information including necessary power information, being information indicative of a power necessary for operating each monitored device itself, and power status information indicative of a received power in each monitored device, causing a power configuration information storage to store the prepared power control information, and further transmitting the prepared power control information to each monitored device. Further, the monitored device includes a power controller for controlling the power of its own device based upon the transmitted power control information.