respectively at the rear portion corresponding to the first chamber 711 and second chamber 712 has an opening that allows a lock head protruding portion 13 to pass through and an aperture 713 that allows the reset member 8 to pass through respectively an embedding slot 714 is recessed below the second chamber 712 the outer cylinder 2 of the key locking mechanism is movably sleeved in the first chamber 711 the snapping piece 6 of the combination locking mechanism is disposed in the second chamber 712 as illustrated the snapping piece 6 comprises a plurality of pairs of symmetrically arranged snapping arms 61 at a front end and on an outer surface of the outer cylinder 2 an outer guiding groove 21 is provided on the interior surface of the outer cylinder 2 an axially extending inner guiding groove 23 is provided further one end of the outer guiding groove 21 is connected to an axially opened positioning slot 22 the lock head 1 comprises a holding head 11 inner cylinder 12 protrusion portion 13 and latch 14 the holding head 11 has a key hole 111 a protrusion 121 radially protrudes at a bottom of the inner cylinder 12 corresponding to the inner guiding groove 23 of the outer cylinder 2 a protruding portion 13 extends from a rear portion of the lock head 1 the lock head 1 comprises a lock core not shown therein the protrusion 121 is retractable and is actuated by a key inserted into the key hole 111 to unlock the lock head 1.