Abstract: A ventilating element of a casing of a lighting or signaling device of a vehicle. The ventilating element comprises essentially a cover with a cavity enclosing a filtering membrane, a mounting surface on a wall of the casing and an end-piece for connecting to an air duct. The filtering membrane is placed on a seat formed in the cavity of the cover, approximately level with the mounting surface. An openwork wall is placed against the filtering membrane on a face of the membrane that is on the other side from the seat in the cavity. The ventilating element is mounted on a wall provided with a dedicated opening so that the peripheral edge of the openwork wall comes into contact with the wall, thus keeping the said openwork wall and the filter in place.