Abstract: An oleopneumatic actuator cylinder device for steering and self-centering for the alignment to a straight drive of steering or self-steering axles, in particular for rear axles of vehicles, is constituted by a single oleopneumatic actuator cylinder for each rear steering axles. The actuator cylinder comprises a pneumatic sector communicating with a respective pneumatic circuit, an oleodynamic sector communicating with a respective oleodynamic circuit, a stem kinetically connected to the a mechanical driving element to move the wheels of the vehicle, and a central body that delimits the pneumatic sector and the oleodynamic sector.