To provide a lock which can change its latch inclining direction through extremely simple work, to thereby change the lock from a right-sided lock mode to a left-sided lock mode or vice versa.

The latch 3 is attached to a connecting member 17 by means of a strong auxiliary spring 20 as if the latch 3 and the connecting member were connected together in one piece. However, when the connection is pried away by a driver, it cannot resist an excessive force, and therefore the auxiliary spring 20 is contracted, whereby the latch 3 axially moves with respect to the connecting member 17. As a result, the latch 3 further outward protrudes from a normally protruding position, whereby engagement of the latch 3 with a guide portion (opening 11) of a front plate 6 is cancelled. Accordingly, the latch 3 is free from rotational restriction, i.e., it is rendered rotational, so that the direction of the latch 3 is changed without removing the front plate 6, whereby the lock can be changed from the right-sided lock mode to the left- sided lock mode or vice versa.