PURPOSE: To perform message transmission or the like while preventing unwanted data from being exchanged between an interrogator and the ID card.

CONSTITUTION: At an ID card 13 to exchange data while being non-contact with an interrogator 1 through microwaves transmitted from the interrogator 1 by providing memory elements, a data processing part 23 is provided to receive a call signal from a caller 27 and to collate the call signal with data in the memory elements, and a display part 25 is provided to display required data when the call signal and the data in the memory elements are coincident. Then, the data processing part 23 controls the transmission and stop of data stored in the ID card 13 while being interlocked with the call signal from the caller 27.