An apparatus for creating network configuration information from data including packet transmission time between one or more relay devices and a terminal, the relay devices relaying a signal which runs through a network and is measured by the terminal connected to the network, to another network, information about the relay devices and information about the terminal. The apparatus includes systems for: receiving the data from the terminal; arranging the relay devices in the network configuration information based on information about the relay devices; arranging the terminal in the network configuration information based on information about the terminal; arranging packet transmission time between the terminal and the relay devices in the network configuration information; and identifying a subnetwork from the data.