To provide a lock with a structure of a key and a keyhole, which eliminates the risk of the loss of the key and which does not require an operating time until unlocking.

The grooves A, B, C, D, E and F are made by making a plurality of holes corresponding to the keyholes and connecting the holes so as to form them like a road. Structurally, a rod-shaped body 1 corresponding to the key can freely move along the grooves. The rod-shaped body corresponding to the key moves along the groove in unlocking. When the rod-shaped body reaches a terminal end part in a certain location in the plurality of grooves, a shackle 2 serves as a trigger for disconnecting a lock part inside the inside 3 of the lock, which is built in a nonslip manner by being inserted into the inside 3 of the lock; and consequently, the shackle 2 is disconnected from the inside 3 of the lock.