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 at least parts of the projected inner diameter side opening portion overlap with an inner circumferential surface of the pocket when viewed from a radial direction of a ball bearing, and a central line of the other radial hole is separated from a circumferential phase of the center.