A steering column mechanism a movable subassembly including a tube body and a steering shaft rotating around an rotation axis in the tube body, and a connecting articulation between the movable subassembly and a fixed support to guide pivoting of the movable subassembly relative to the fixed support around a pivot axis perpendicular to the rotation axis. An antitheft locking mechanism includes a locking body that is movable relative to the fixed support between a retracted position and at least one locking position and a matching member mounted on the shaft. In the locking position, the locking member ensures with the matching member positive locking to lock the rotation of the steering shaft. The locking member and the matching member have, in the locking position, a mutual contact zone which, in reference to a direction parallel to the rotation axis, extends on either side of the pivot axis.

A steering column assembly includes a jacket assembly and a bracket. The bracket has a first end portion defining a first opening and a second end portion defining a second opening. The second end portion overlaps the first end portion such that the second opening and the first opening are proximately aligned.

A steering device includes: a first shaft that holds an operating member; a second shaft; a first tube that moves with the first shaft; a second tube that guides the first tube; a moving mechanism that moves the first tube to a first region in which the first shaft is allowed to rotate and a second region in which the first shaft is not allowed to rotate; a lock piece disposed on the proximal end side with respect to the first tube positioned in the first region; and a biasing member that biases the lock piece. When the first tube is positioned in the second region, the lock piece engages with an engaged portion provided on the first shaft so as not to allow the first shaft to rotate.