A cup/valve assembly for an aerosol container, made up of a cup, a valve body, a stem, a spring, and an inner seal. The stem comprises a bulge on its outer cylindrical face and an inner conduit which has an upper opening at its upper end and at least one lateral orifice at its lower end between the bulge and the upper opening of the inner conduit. The valve body has an opening at its upper end. The valve body is fixed to a central opening (23) of the cup leaving the opening in the cylindrical portion free, and the stem is retained in the valve body by a retaining ring (5) that surrounds, without tightening, the stem, and is fixed to the cup, the inner seal (13) being interposed between the retaining ring (5) and the top edge of the cylindrical portion of the valve body.