Patent ID: 8123630

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 rubber material and has a hardness which gradually increases from a center to a surface thereof, the hardness difference in JIS-C hardness units between the core center and the core surface being at least 15 and, letting (I) be the average value for cross-sectional hardnesses at a position about 15 mm from the core center and at the core center and letting (II) be the cross-sectional hardness at a position about 7.5 mm from the core center, the hardness difference (I)−(II) in JIS-C units being not more than ±2; and the envelope layer, intermediate layer and cover have hardnesses which satisfy the condition: cover hardness>intermediate layer hardness>envelope layer hardness, wherein the intermediate layer has a lower hardness than the cover in which the hardness difference (Shore D) between the cover and the intermediate layer is 3 to 20, and wherein the envelope layer, intermediate layer and cover have thicknesses which satisfy the condition: cover thickness<intermediate layer thickness<envelope layer thickness.