Abstract: An anti-theft device for vehicles includes a central block rotationally fixed to a steering wheel and having a central cavity therein. A lock member is rotatably supported in said cavity and carries at a free end thereof a frontal lift cam. An inner cam is rotatably supported in the central block cavity and is rotationally fixed to a steering rod. A pair of diametrically opposed grooves is formed in the inner cam. A movable crossmember is disposed in the central block cavity between the frontal lift cam and the inner cam, and is carried with the central block for rotation. The frontal lift cam, when rotated, engages against and presses the crossmember into the grooves of the inner cam, thereby locking the inner cam to the central block for rotation therewith. A spring biases the crossmember outwardly from the inner cam grooves.