PURPOSE: To make decoding impossible, and thereby prevent burglar by letting the device be equipped with a memory means, a code producing means and with a means outputting a first and a second produced code to the outside.

CONSTITUTION: A transmitter 100 allows a transmitting circuit 101 to transmit coded 'fixed numbers' and 'code numbers' to a receiving side via an antenna 102. At the side of an automobile as a receiver, it is equipped with an antenna 201 receiving electric waves from the transmitter, a receiving circuit 202 and with a decoding mechanism 203. The receiving circuit 202 receives the coded 'fixed numbers' and 'code numbers' so as to compound them. The receiving circuit 202 stores the 'fixed numbers' and 'code numbers', the stored 'fixed numbers' and 'code numbers' are compared with the compounded 'fixed number' and 'code number', and it is then determined whether or not the lock is released.