To obtain a hollow molding method which makes the wall thickness distribution of a molded article uniform, a molding mold, and molding machine.

In a blow molding method to obtain a hollow molded article by expanding a parison arranged in a mold, while the parison being expanded, fluid is sprayed toward a part, in which the variation in the wall thickness of the parison is small, from an inlet 2 which is formed in a cavity surface and from which fluid is introduced into the cavity 16, and the fluid is discharged forcibly from an outlet 3 which is formed in the cavity surface at a position corresponding to a part in which the wall thickness variation of the parison is large. The wall thickness distribution of the molded articles can be made uniform even for the article having a complex shape.