PURPOSE: To enable the locked state of the opening sections of a service entrance, windows, and the like to be controlled with the natural working of locking a vestibule by receiving locking signal transmitted from a vestibule lock, at a control section, and by driving an alarm under the condition that the locking signal and the releasing signal of an opening lock are received at the same time, to generate release alarm output.

CONSTITUTION: By a control section 14, first, under a condition that the door opening signal of a service entrance lock 11 is received, an alarm 13 is driven and release alarm output is generated. After that, under a condition that the door opening signal of the service entrance lock 11 is not received but the lock releasing signal of the service entrance lock 11 is received, the alarm 13 is driven and released lock alarm output is generated and the service entrance lock 11 is locken by electric operation. In this case, the locked and released lock detecting switchgears 15, 17 of the service entrance lock 11 and a vestibule lock 12 are composed in the same manner as those of electric locks, and locked and released lock signal is issued.