To prevent fraudulent unlock by picking and a duplicate key with remote control and automatic switching from an outdoor side, besides from an indoor side, by solving the problem wherein a crime related to lock such as unlock by a duplicate key and picking is increased and any strong lock is powerless against the crime by picking and duplicate keys, and furthermore, the duplicate key can be copied and possible to be lost and it is difficult to cope with unlock by picking and the duplicate key, which is performed without breaking a building, in maintenance and guard of the building.

In order to prevent unlock of the lock by the duplicate key nor picking, a dead lock bar is provided inside a lock case, and the dead lock bar is electrically moved to fix a dead bolt or to release the fixation. With this structure, unlock by the duplicate key and picking can be prevented in the dead lock condition wherein the dead bolt is fixed.