Abstract: A network management program is executed in a managing device for managing network which includes multiple devices to be managed and plural managing devices. The network management program comprises computer instructions for exchanging management information between said plural managing devices, judging in accordance with said exchanged management information whether said plural managing devices are performing duplicative management with respect to the same managed device or not, and making only one of said plural managing devices manage said device duplicatively managed. The network management servers (managing devices) comprising computers operates in accordance with the network management program installed in memory on both computers so as to prevent dupulicative management of the multiple devices to be managed belonging to the network.