Patent ID: 8905863

Claim:
A multi-piece solid golf ball comprising a core, an envelope layer encasing the core, an intermediate layer encasing the envelope layer, and a cover which encases the intermediate layer and has formed on a surface thereof a plurality of dimples, wherein the core is formed primarily of a thermoplastic resin and has a diameter of from 20 to 30 mm, the envelope layer is formed of a rubber composition containing primarily a rubber material and has a thickness of from 3 to 10 mm, the intermediate layer is formed of a resin composition containing primarily an ionomer, and the cover is formed of a resin composition containing primarily a urethane; wherein the intermediate layer has a specific gravity of less than 1.0, and the core, the envelope layer and the intermediate layer have specific gravities which satisfy the condition: core specific gravity<envelope layer specific gravity>intermediate layer specific gravity; and wherein the core, the envelope layer, the intermediate layer and the cover have Shore D surface hardnesses which satisfy the condition: core surface hardness<envelope layer surface hardness<intermediate layer surface hardness>cover surface hardness.