Multi-piece solid golf ball

1. A multi-piece solid golf ball comprising a core, an intermediate layer and a cover, wherein the core is formed primarily of a base rubber and has a diameter of at least 32 mm, the intermediate layer and the cover are each formed of a resin material, the core has an internal hardness which is such that, letting Cc be the Shore C hardness at a center of the core, C2 be the Shore C hardness at a position 2 mm from the core center, C4 be the Shore C hardness at a position 4 mm from the core center, C6 be the Shore C hardness at a position 6 mm from the core center, C8 be the Shore C hardness at a position 8 mm from the core center, C10 be the Shore C hardness at a position 10 mm from the core center, C12 be the Shore C hardness at a position 12 mm from the core center, C14 be the Shore C hardness at a position 14 mm from the core center, C16 be the Shore C hardness at a position 16 mm from the core center, Cs be the Shore C hardness at a surface of the core, Cs-3 be the Shore C hardness at a position 3 mm inside the core surface and Cm be the Shore C hardness at a position midway between the core surface and the core center, the values of C8-C6, C6-C4, C4-C2 and C2-Cc are all 4.0 or less and the values of C16-C14, C14-C12, C12-C10 and C10-C8 are all 5.5 or less, and which satisfies formulas (1), (2) and (3) below

Cs−Cc≥ 22  (1)

( Cs−Cm )/( C 4− Cc )≥4.0  (2)

Cs−Cs− 3≤5.0  (3);

and the sphere obtained by encasing the core with the intermediate layer (intermediate layer-encased sphere) has a Shore C surface hardness and the ball has a Shore C surface hardness which satisfy the following relationship:

surface hardness of intermediate layer-encased sphere<surface hardness of ball (4); and

wherein the core is formed of a rubber composition comprising:

(a) a base rubber,

(b) a co-crosslinking agent that is an α,β-unsaturated carboxylic acid or a metal salt thereof or both,

(c) a crosslinking initiator, and

(d) a lower alcohol having a molecular weight of less than 200.

2. The golf ball of claim 1 , wherein the core internal hardness is such that, in the measured hardnesses obtained by measuring the Shore C hardness at 2 mm intervals outward from the core center but not measuring the hardness at the position 2 mm inside the surface, letting the differences between the adjoining measured hardnesses from the core center outward be respectively A 0 , A 1 , A 2 , A 3 . . . , these adjoining measured hardness differences in turn have differences therebetween, defined respectively as A 1 -A 0 , A 2 -A 1 , A 3 -A 2 , . . . , which are all values of 3.5 or less.

3. The golf ball of claim 1 , wherein the core consists of a single layer.

4. The golf ball of claim 1 , wherein a coating layer is formed on a surface of the cover and, letting Hc be the Shore C hardness of the coating layer, the difference Hc-Cc between Hc and the Shore C hardness Cc at the core center is at least −12 and not more than 20.

5. The golf ball of claim 1 , wherein the content of component (d) is from 0.5 to 5 parts by weight per 100 parts by weight of the base rubber (a).

6. The golf ball of claim 1 , wherein component (d) is a monohydric, dihydric or trihydric alcohol.

7. The golf ball of claim 1 , wherein component (d) is butanol, glycerol, ethylene glycol or propylene glycol.