abstract |
A golf ball 2 includes an inner core 4, an outer core 6, a mid layer 8, and a cover 10. A diameter D1, a volume V1, a hardness H1o at a central point, and a boundary inside hardness H1in of the inner core 4; a volume V2, a boundary outside hardness H2out, and a surface hardness H2s of the outer core 6; a thickness Tm and a hardness Hm of the mid layer 8; and a thickness Tc and a hardness Hc of the cover 10 meet the following mathematical formulas (1) to (4): 1.0<V2/V1<7.0 (1); −2<H2s−H2out<2 (2); 600<(H1o+H1in)*(D1/2)/2<1000 (3); 620<Tc*Hc*Hm/Tm<900 (4). The cover 10 includes a polyrotaxane. |