To easily improve operability while maintaining crime preventive performance.

This device has a pair of locking units for arranging a cylinder lock, lock boxes 10 and 60 and indoor side units 20 and 70 in this order from the outdoor side and capable of locking and unlocking even from both the indoor and outdoor sides, and a switching mechanism provided in the pair of locking units and capable of automatically switching an interlocking state capable of locking or unlocking the other locking unit via locking-unlocking operation from the indoor side of one locking unit or locking operation from the outdoor side of one locking unit and an uninterlocked state unable to unlock the other locking unit even via unlocking operation from the outdoor side of one locking unit.