A golf ball is provided which contains a core and a cover. In the forming of the cover, two half shells made from a thermoplastic resinous composition are used to cover the core, the composite is put in a spherical mold, then, the mold is clamped. Thereafter, the thermoplastic resin where it is heated and pressurized at a pressure of 5 kgf/cm.sup.2 to 50 kgf/cm.sup.2, and the excess thermoplastic resin composition flows out of the spherical cavity. Subsequently, the thermoplastic resin composition is heated in the spherical cavity and is pressurized at a pressure of 70 kgf/cm.sup.2 or more whereby the cover is formed. The total volume of the two half shells is 105% to 120% of the volume of the cover.