PURPOSE: To prevent generation of casting defects such as central shrinkage cavity, etc. and to obtain a defectless product provided with a vane part by using a composite casting mold consisting of a die for forming the outside peripheral part of a casting and a refractory casting mold for forming the vane part and boss part in performing vertical centrifugal casting.

CONSTITUTION: Vertical centrifugal casting is performed by using a die 1 having large cooling power for forming the outermost peripheral part of a casting, for example, the outside periphery of the shroud part 3c of an impeller for a pump and a refractory casting mold 2 having small cooling power for forming a vane part 3b and boss part 3a. The cooling of the molten metal 3 in the vane part 3b and boss 3a is thus retarded. The generation of casting defects such as central shrinkage cavity or the like in the vane part 3b is prevented by such directional solidification. The inclusions in the molten metal further centrifugally separated by centrifugal casting and are accumulated in the riser part 3d above the boss part 3a and therefore the product provided with the vanes having the defectless internal quality is thus cast.