To provide a method for manufacturing a molding material, capable of improving the inner diameter precision of a trunk, and reducing a risk of trim deficiency.SOLUTION: A method for manufacturing a molding material includes manufacturing a molding material 1 having a cylindrical trunk 10 and a flange part 11 formed in an end part of the trunk 10 by subjecting a raw material metal plate 2 to multistage drawing. The multistage drawing includes: preliminary drawing for forming a preliminary body 20 having a trunk element 20a from the raw material metal plate 2; and at least one-time compression drawing for forming the trunk 10 by drawing the trunk element 20a after the preliminary drawing while adding compressive force along a depth direction of the trunk element 20a to the peripheral wall of the trunk element 20a. In the preliminary body 20, earring with a wave-shaped end part is generated, and in the compression drawing, compressive force is adjusted so as to bring the roundness of the flange part 11 to equal to or less than a prescribed dimension.SELECTED DRAWING: Figure 2