A coating for a structure with an integrated airbag has a coating element which has a portion operative for covering an airbag box and being perforated in a region of an edge of the portion for covering the airbag box. An entire region of a left side lens region of the convex lens is constituted as upper deflecting regions for deflecting light to a direction upward with respect to a direction of light of a right side lens region. The respective backup rolls are offset slightly upstream of the respective bias transfer rolls.