Device for activating mandibular growth maxillary growth and mandibular advancement said device comprising: a first rod (3) with a front end (9) and a rear end (10); a second rod (4) with a front end (11) and a rear end (12); said first (3) and second (4) rods being relatively rigid and having mutually different lengths; a first pivoting articulation (6) for connecting the front end (9) of the first rod (3) to a first dental arch of a person; a second pivoting articulation (8) for connecting the front end of the second rod (4) to the second dental arch of the person; a third pivoting articulation (7) interconnecting the rear ends (10, 12) of the rods (3, 4) and allowing the device to change from an open position to a closed position and thus follow the movement of opening and closing of the jaws characterized in that said third pivoting articulation (7) is able to be connected to the dental arch carrying the shortest rod with the aid of elastic means (5) returning the device to the closed position in such a way that said rods are able to induce a movement of the mandibular arch relative to the maxillary arch in the closed position of the jaws.