A coated film with no observable streak is formed. The landing positions of a first discharge liquid discharged through a first printing head and the landing positions of a second discharge liquid discharged through a second printing head are disposed in a mixed manner in an area on a substrate where the first printing head and the second printing head overlap. Which discharge liquids are to be landed is determined according to random numbers. Since a coated film which is formed with the first and second discharge liquids in a mixed manner is disposed between a coated film formed with the first discharge liquids and a coated film formed with the second discharge liquids, a boundary is obscured and no streak appears.