The invention provides a multi-piece solid golf ball composed of a solid core, a cover, at least one intermediate layer interposed therebetween, and a plurality of dimples on a surface of the ball. The respective initial velocities (m/s) of the core, a sphere I composed of the core encased by the intermediate layer, and the golf ball satisfy formula A below, and the respective deflections (mm) of the core, the sphere I composed of the core encased by the intermediate layer, and the golf ball, when compressed under a final load of 130 kg from an initial load of 10 kgf, satisfy formula B below: (initial velocity of core−initial velocity of sphere I)2+(initial velocity of sphere I−initial velocity of golf ball)2