From a data terminal device (3), a position notifying device (1) acquires a position request for requesting position information of a target object and identification information, with identification information for identifying the data terminal device (3) being stored in a storage section (11). In response thereto, the position notifying device (1) determines whether the currently acquired identification information is stored in the storage section (11) or not. If the identification information is stored, the position notifying device (1) generates position information of the target object, and sends the position information to the data terminal device (3).