PURPOSE: To improved the security by setting an operable time in response to an operation level, inserting a selector card within the time and releasing a corresponding electromagnetic lock.

CONSTITUTION: An operator inserts a selector card 1 into a selector-card 1 inserting port, and the card 1 is read by a card reader. The operator inputs a password number by a keyboard, and the previously registered password number and an input number are collated by a lock control section 2. When both numbers coincide at that time, a registered card is inserted by the operator, and the registered number is collated in a memory and control is transferred to lock control when the number is registered previously. The lock control section 2 releases all electromagnetic locks 4 by operable information from a monitor at that time. An operable time corresponding to the selector card 1 is extracted from the memory, a current device state is obtained from the memory and the operable state is confirmed at the time except the operable time, and locking is released.