The invention provides a signaling device for a motor vehicle, the signaling device being constituted by a skin of translucent material presenting an outside face to be seen from outside the vehicle when said device is mounted on the vehicle, and an inside face opposite the outside face. Projecting from its inside face, translucent skin has at least one rib made integrally with the skin and out of the same translucent material as the skin. The thickness of the rib is greater than the thickness of the translucent skin.