To provide a multi-layered game ball produce by reducing the number of production stages.

An inner-layer precursor is extruded as a parison 22 while being partially melted, the outer layer 14 is formed, the inner layer 12 and the outer layer 14 are introduced into a die 24, the parison 22 is expanded in the die 24 so as to be formed into a multi-layered game ball product 10. The outer layer 14 may be a preliminarily-cut panel which is supported in the die 24 by vacuum, or an intermediate layer 16 may be provided in the product for the safety in the dimension. Successively to the expansion of the parison, filler such as foam may be injected so as to form a core.