To easily discriminate locked state or unlocked state for a lock by a method wherein letters or patterns different from each other are attached separately to a turning member and a fixed member of the lock.

A pattern a2 is attached to a turning member 1 of a lock while a pattern b4 is attached to a non-turning or fixed member 3 of the lock. As a key is inserted into a keyhole 7 provided at the turning member 1 and turned for locking, the pattern a2 turns concurrently. With the key extracted after locking, positions of the pattern a2 and the pattern b4 are varied as compared with positions before locking. Therefore, discrimination between the locked state and the unlocked state can be made easily only by confirming positional relation between the pattern a2 and the pattern b4.