Abstract: A linkage anti-theft lock head comprises a lock tube (16), a lock core (2), a brake bar (19), a front tumbler (6) with its return spring (20), a rear tumbler (9) with its return spring (20) and a key (1). Clearance fits are provided between the front tumbler (6) and the rear tumbler (9) with the holes (26) distributed axially on the lock core (2). The brake bar (19) is mounted axially along the lock core (2). Brake teeth of the brake bar (19) engage with the teeth grooves of the front tumbler (6) and the rear tumbler (9). Said engagement is a linkage engagement. A brake groove (17) is set on the lock tube (16) to match with the brake bar (19). The tumblers, the brake bar (19) and the lock core (2) constitute a cant device, wherein the front tumbler (6) and the rear tumbler (9) act as moving cams set oppositely, the brake bar (19) acts as a driven member and the lock core (2) acts as a rack.