PURPOSE: To make injection molding of a cover by surely aligning a core center to a cavity center and to simplify metal mold formation so as to inexpensively produce a golf ball by projectingly providing the front surface of a core for the golf ball with plural pieces of convex projections of the same height.

CONSTITUTION: This solid core 1 is randomly and projectingly provided with plural pieces of the hemispherical convex projections 2 of the same height on its front surface. The heights of the respective projections 2 are set at the same height as the thickness of the cover layer formed on the outer periphery of the core 1 so that the front ends of the respective projections 2 come into contact with the cavity surface when the core is inserted into the cavity of the metal molds for injection molding for the purpose of molding the cover. The core 1 is put into the cavity 4 of the metal molds 3 for injection molding at the time of producing the golf ball. This core 1 is arranged without eccentricity in the central part in the cavity 4 by the presence of the projections 2. The golf ball formed with the cover layer by injecting a cover forming material in the cavity in this state is obtd.