A fixing board, for an attraction-fastening type freight carrying device to be mounted on the roof of a motor vehicle, has been improved. The fixing board is composed of a magnetic attraction force contact plate, a film-like suction-cup, and a releasing handle. The magnetic attraction force contact plate has a three-layer structure comprising a soft magnet plate, an iron plate and smooth thin-film sheet coated on the iron plate. The iron plate has a plurality of grooves radially extending, which are elongated dead-end grooves. Further, the magnetic attraction force contact plate has a through-hole into which a substantially cylindrical seal lip extending from the suction film is inserted so as to make an air value. This air hole takes on a closed state when the freight carrying device is installed on the vehicle roof, and takes on an open state when being removed therefrom. The film-like suction-cup is formed throughout the circumference of the magnetic attraction force contact plate.