A first terminal accompanying a subject moving entity transmits a first time-sequential data string, which represents a history of a first state quantity varying depending on a behavior of the subject moving entity, to a second terminal wirelessly. The second terminal stores a second time-sequential data string representing a history of a second state quantity of a moving entity detected by a moving entity detector in association with the moving entity detected. The received first time-sequential data string and the stored second time-sequential data string are referred to so as to identify the association between (i) the first terminal, which is equivalent to a transmission source of the first time-sequential data string, and (ii) an identified moving entity that is identified from the detected moving entity, to determine that the identified moving entity is associated with the first terminal.