PURPOSE: To facilitate locking and unlocking operation by a method wherein the inner cylinder body of axially movably constituted cylinder lock and a pinion fitted in a tail piece are arranged in the same outer case and a relative position relation therebetween is kept unchanged.

CONSTITUTION: An inner cylinder body 33 of a cylinder lock 29 mounted in an outer case 16 is movable to an outer cylinder block 31, and a vertically movable L-shaped lack plate 36 is engaged with a pinion 35 fitted in a tail piece 32. In a case of, for example, locking, a duplicate key 37 is inserted to advance a cylinder body 33 and a locking arm 22L and an unlocking arm 22-UL carried by a holder 17 are protruded. A key 37 is turned, the arm 22-UL is raised through the plate 36, and a hook 7 is rotated through an engaging protrusion 11 and 8 drive plate 8. This constitution, since the cylinder body 33 and the pinion 35 are arranged in the same case 16, performs reliable actuation and facilitates operation.