This invention relates to a car safety belt, constituted by a diagonal element combined with a subabdominal element by a means for selectively maintaining the orientation of the two elements of the belt and by a buckle, the means for maintaining the orientation of the two elements being constituted by a sleeve which concomitantly envelops the elements, one of the ends of which abuts on the buckle and the other end of which holds the zone of intersection of the two elements in the preferred position.