A ball bearing includes: an inner ring having an inner ring raceway surface on its outer circumference; an outer ring having an outer ring raceway surface on its inner circumference; a plurality of balls are disposed between the inner and outer ring raceway surfaces; and a cage. In the outer circumference of the inner ring, an inner ring shoulder portion is provided on a first axial side of the inner ring and a counter bore is provided on a second axial side of the inner ring. A tapered surface extending radially outward toward the ball is formed in a portion that is in a circumferential wall of each pocket hole, and that is in an end on a first axial side of the cage.