A terminal apparatus generates a hash value from a sequence number based on a predetermined hash algorithm, and creates identification information from an IP address and/or a MAC address and the generated hash value based on a predetermined creation algorithm. Moreover, at the time of processing for shutdown or reboot, the terminal apparatus stores the current recording device information into a hard disk, and when booted next time, determines whether or not the current recording device information and the recording device information stored in the hard disk match with each other. Further, when booted, the terminal apparatus requests a response from another terminal apparatus in the network segment, and when there is not a response from another terminal apparatus, creates management information of terminal apparatuses including itself having been booted in the network segment. With this, spoofing as an authorized terminal apparatus can be prevented, a change of a recording medium can be monitored, and the traffic of the communication network needed for the management of the terminal apparatuses can be reduced.