Abstract: A fastening device including a housing element, a body rotatable for at least an arc in the housing element, and a resilient element located between the housing element and the body. The resilient element has arms movable between a disengagement position, at which the arms are near one another and extended, and an engagement position, at which the arms are moved away from one another and retracted for a traction engagement with the walls of an engagement hole. The body has cam parts for forcing the arms from the disengagement position to the engagement position, when the body is rotated.