A ball bearing includes an outer ring (2); an inner ring (3); a plurality of balls (4); and a cage (17) that has an annular shape. Oil flows into an area between the outer ring (2) and the inner ring (3) from one side in an axial direction and flows out from the other side in the axial direction. The cage (17) includes an annular portion (5) provided on an oil inflow side, and bar portions (7) extending from the annular portion (5) toward an oil outflow side. An outer peripheral end portion of the annular portion (5) is constituted by a corner portion (52) at which an axial outer end face (19) intersects with an outer peripheral surface. An axial position of a tip end of the corner portion (52) is substantially same as an axial position of a side surface of the outer ring (2).