A golf ball 2 has a spherical core 4, a mid layer 6 situated on the external side of the core 4, and a cover 8 situated on the external side of the mid layer 6. The core 4 has a spherical center 10 and an envelope layer 12 situated on the external side of the center 10. At all points P included in a zone away from the central point of the core 4 at a distance of 1 mm or greater and 15 mm or less, the following mathematical expression is satisfied. H2−H1≦5 In the above mathematical expression, H1 represents the JIS-C hardness at a point P1 that is located inside the point P along the radial direction and away from the point P at a distance of 1 mm, and H2 represents the JIS-C hardness at a point P2 that is located outside the point P along the radial direction and away from the point P at a distance of 1 mm.