PURPOSE: To improve security by previously memorizing the second signal into a RAM in an ID card and reading the second signal when the first signal inputted from a key switch accords with the second signal.

CONSTITUTION: A key switch 21. RAM 25b, CPU 25a, and a display element 22 are assembled into an ID card 20. The second signal is previously memorized into the RAM 25b, and in the use of the card 20, the first signal is inputted by operating the key switch 21. Then, the both signals are collated by the CPU 25a, and when the both signals accord, the second signal, is read out, and the corresponding data is displayed onto the display element 22. When the ID card 20 is inserted into a card reader 30, the second signal is read out, and the release of locking for a controlled facilities is controlled by a lock controlling computer 40. Therefore, the bad use of the lost card can be prevented, and the application range for a variety of use can be spread.