When inner diameter side opening portions are projected on an outer circumferential surface of a retainer along extension lines of central lines of radial holes, at least parts of the inner diameter side opening portions of a plurality of radial holes of an outer ring are positioned within an area of two circles formed by connecting each of axial end portions of adjacent pockets of the retainer in an axial direction. When a central line of any one radial hole coincides with a circumferential phase of a center of a ball, any other radial hole is formed such that the projected inner diameter side opening portion is separated from the ball and an inner circumferential surface of the pocket when viewed from the radial direction of the ball bearing, and a central line of the other radial hole overlaps with the pocket when viewed from the axial direction.