PURPOSE: To improve the resilience performance by preparing a cover covering a core from a material containing a specific Li ion ionomer as main constituents.

CONSTITUTION: The main component is Li-ion ionomer which has a melt index of 0.5-5.0 and a Shore D hardness of 60-80 and in which 20-70mol% of the carboxyl group of the ethylene-α,β-unsaturated carboxylic acid copolymer containing cover α, β-unsaturated carboxylic acid in 10-20wt% are neutralized by Li ions. Thus, the used ionomer resin has a base resin made of the copolymer of ethylene and α,β-unsaturated carboxylic acid, and the quantity of carboxylic acid is 10-20wt%. When the quantity of carboxylic acid is less than 10wt%, the quantity of carboxylic acid is short, and the superior resin in metal ion neutralization can not be obtained, and rigidity reduces, while if the quantity exceeds 20wt%, the resin having high neutralization degree is hardly prepared, and rigidity increases excessively, and a brittle resin is formed, and hardly used in actual use. Therefore, the resilience of the golf ball can be improved.