Abstract: A gypsum board manufacturing method is provided. The gypsum board manufacturing method includes a molding step of forming a plate-shaped molded body including gypsum slurry and cover base paper disposed to cover at least a part of a surface of the gypsum slurry. In a cross section orthogonal to the longitudinal direction of the molded body, the cover base paper completely covers the periphery of the gypsum slurry, portions of the cover base paper overlap each other, and a distance between a step formed by the overlap of the cover base paper and a lateral end of the molded body is greater than or equal to 15 mm.