There is disclosed an information processing system having plural IC tags (e.g. RFID tags), each of which transmits back a signal in response to an interrogatory signal sent from a cell phone acting as an interrogator. The information processing system includes the RFID tags and the cell phone. The cell phone transmits an interrogatory signal to the tags to read information from the tags. Each tag receiving the interrogatory signal transmits positional information stored in the tag to the cell phone in response to the interrogatory signal. The cell phone transmits a specific interrogatory signal including at least one of the transmitted sets of positional information. Each tag receiving the specific interrogatory signal makes a decision as to whether the positional information contained in the specific interrogatory signal matches the positional information stored in the tag itself. According to the specific interrogatory signal and the result of the decision, information contained in at least one of plural storage regions is transmitted to the interrogator.