A high-speed ball bearing includes an outer ring, an inner ring, a plurality of balls, and a ball retainer. The ball retainer includes a plurality of pocket holes for arranging a plurality of balls, an inner circumferential surface of each of the pocket holes have a spherical surface is coaxial to the ball. A gap between an outer circumferential surface of the ball retainer and an inner circumferential surface of the ring is defined as a first gap, and a gap between the pocket hole and the corresponding ball is defined as a second gap. The first gap and the second gap have the following relationship: W2=(W1−r′)×A.