To improve locking reliability by abolishing use of a keyhole and a key so as to unlock by only a transmitted signal so that a mischief is hardly made and increasing the number of codes of a discrimination code signal to increse the number of counts of the lock.

A signal from a receiver 21 is compared with a signal of a discrimination code signal generator 23 by a coincidence detector 22. When it coincides therewith, a coincidence signal is transmitted to a gate 24. Further, the coincidence signal is transmitted from a battery alarm 27 to an unlocking drive 25 for an unlocking motion. In this time, if the remaining capacity of a battery 26 is lower than a specified level the alarm 27 informs a user thereof and the coincidence signal is prevented from being transmitted to the unlocking drive 25 to make it unlockable. A signal transmittion button 12 is depressed while operating a lever detector 28 of a receiver 20 by an urgent unlocking lever 16 provided in a transmitting means 10 to temporarily transmit a coincidence signal to the unlocking drive 25. In this way, unlocking operation can be manipulated by the urgent unlocking lever 16 for only a short time. Hence, the battery 26 can be replaced for unlocking in this time.