The tip of a downstream lip is disposed so as to be further separated from a web as compared to the tip of an adjacent lip, and downstream and upstream spacers are placed so that the a liquid discharge port length interposed between two downstream spacers is shorter than that of a liquid discharge port interposed between two upstream spacers. The method includes coating coating-liquid to the surface of the web from a slot die, which is formed so that tips of the downstream spacers are placed at the same position as a tip of the adjacent lip or further protrude so as to be closer to the web than the tip of the adjacent lip; depressurizing the cover inside that is provided on the upstream side of the slot die during the coating; and drying the coating-liquid that is coated to the surface of the web.