To be capable of coating without forming a clearance while almost preventing a double-coated part from rising even when the part is coated with its ends laid to overlap each other in a wide-slit nozzle.

In the example 1 using the wide-slit nozzle 1, x=15 mm, y=14 mm, α=0.3 mm, and β=0.6 mm. Accordingly, the total length (width) of a slit 2 is 15+14×2=43 (mm). However, since a coating material is discharged with pressure applied from the slit 2, the material is applied while being largely expanded as compared with the width of the slit 2. In all examples, the material is discharged at speed of 7 liters per minute, and in the example 1, the width of application is 100 mm. Even when the width (lap part) z of the double-coated part p2 is 10 mm, or 20 mm, the increase rate of the thickness of the double- coated part p2 is +25% to be very small, so that the interference with a component arranged on a floor, piping passed on the floor, etc., is prevented.