To make it possible to mount a handle on the door surface of a door in either vertical direction or horizontal direction with one kind of lock main body, one kind of handle and seat and to enable one kind of lock main body convenient to use as the vertical handle or the horizontal handle at a low cost.

A handle movably provided on the door surface of a door (a) through a seat and to be pushed or pulled in the direction of door opening can be mounted on the door surface of the door (a) selectively in either vertical direction or horizontal direction. A locking piece 10, a vertical handle interlock releasing device 20 and a horizontal handle interlock releasing device 50 are provided to the inside of a lock case 1A, one of first operating plate 9a and second operating plate 9b connected to the handle makes the vertical handle interlock releasing device 20 and horizontal handle interlock releasing device 50 operate by pushing or pulling the handle, the locking piece 10 is pivoted in the interlock releasing direction to separate the interlocking piece 12 from an interlocking groove 4d of a latch head 4, and the interlock thereof is released to make it possible to open the door.