Abstract: A vehicle raising jack has an arm with a stirrup, at least one flat front support portion, at least one arm to which the jack foot is pivotally connected and a nut in which the jack screw is threaded. The jack has an automatic stabilizing and reinforcing structure including a convex member, rotatably retained and supported on a transverse rod attached to the arm by a hook and by respective end flanges. The stirrup is pivotally supported on the convex member and carries a center plate member, located in front of the stirrup and under the flat front support portion thereof. The stirrup is provided with a downwardly projecting flap attached to the bottom of the plate member, in which there is mounted a spring attached at the other end thereof to the arm and holding the stirrup centered.