To provide a lock, which is small in size and can open a door by retracting and entering a latch by the slight rotary operation of a lever handle.

In the lock 1 in which the latch 14 is projected and retracted to and from a lock body 10 in response to the rotation of a hub 20, the lock 1 has a transmission member 19 transmitting driving force corresponding to the rotation of the hub 20 and a driving piece 18 driving the retracting and entering of the latch 14 by driving force transmitted through the transmitting member 19, and the driving piece 18 is constituted so that one end is supported rotatably to the lock body 10 while the other end is engaged with the rear section of the latch 14.