PURPOSE: To miniaturize a switch case by providing a rod with a magnet which operates a magnetic sensing switch as a rotor is rotated by insertion of a key plate, the rod transmitting rotation of the rotor to a lock mechanism.

CONSTITUTION: A rotor 1a is rotated by control of a key being inserted into a cylinder lock 1, and a lever 3 is rotated in conjunction with the rotor 1a. Then a rod 5 held in a holder 4 moves vertically to operate a lock mechanism. When the lock is unlocked, a magnet 6 is located above and perpendicular to an unlock-detecting reed switch 7a. Then the unlock-detecting reed switch 7a is operated by the magnet 6 and detects the unlocked state. When the lock is locked, the magnet 6 is located above and perpendicular to the unlock- detecting reed switch 7b. Then the unlock-detecting reed switch 7b is operated by the magnet 6 and detects the locked state.