In a multi-piece solid golf ball having a rubber two-layer core consisting of an inner layer and an outer layer, a cover, and at least one intermediate layer therebetween, the inner core layer has a diameter of at least 30 mm, the difference in JIS-C hardness between the center of the inner core layer and the surface of the outer core layer is at least 25, the ball satisfies the relationship A/B≦1.5, where A and B are the deflections of, respectively, the inner core layer and the two-layer core when compressed under specific loading conditions, and the intermediate layer has a higher material hardness than the cover. This ball enables mid- to high-level golfers both to achieve even longer distances and to maintain the spin performance on approach shots at a high level.