A semi-molten or semi-solid molding method is used to cast a scroll member having a tabular panel, a spiral section and a columnar part. The method includes filling a cavity formed inside of the molding die with semi-molten or semi-solid metal from a section for forming the columnar part via a runner that forms a channel. The cavity forms a space for casting the scroll member. An angle of intersection θ1 between the runner and the section for forming the columnar part is set such that to 97°≦θ1≦135°, and/or a ratio R/√S is set such that 0.12≦R/√S≦0.96. R is a radius of curvature of a chamfered section in which the runner intersects the section for forming the columnar part, and √S is the square root of a cross-sectional area S of the section for forming the columnar part.
