PURPOSE: To prevent an accident of inability of unlocking by providing code setting means which enables rotating motion for locking of locking means when at least one of a plurality of code dials is turned to set unlock number.

CONSTITUTION: At least one code dial 5 is turned so that a user displays an arbitrary number at a window 1b of a cover 1, and the outer periphery 24 of a cylinder lock 4 is turned by key operation. Then, a recess 9a of lock pin 9 abuts against a recess 24b of outer cylinder 24, and a first bushing 15 abuts against the outer periphery 24 and moves in C direction. Next, an outer peripheral gear 11a of each lock gear 11 engages with an inner peripheral gear 5b of the code dial 5. The unlock number showing the current position of the code dial 5 is stored mechanically by a lock gear 11.