Abstract: From knowledge of the fact that the pattern of the film of coating produced on a surface by spray coating varies with the distance between the nozzle of the spray gun and surface, the nozzle 2 of a spray gun 1 that is disposed facing an outermost end of a surface to be coated is axially inclined so that the external ridge-line of the fan-shaped spray produced thereby is almost perpendicularly with or slightly inwardly inclined to the plane of the surface, the distance as measured along the ridge-line between the nozzle and the surface being selected so that the spray gun can produce in the surface W a film of coating sharply defined at the contour, without unwanted spots of paint called the "tails" at both ends of the film.