To provide a retainer for a ball bearing, which reduces a shearing resistance of an oil film functioning between a pocket inner peripheral surface and a surface of a rolling element (ball), and at the same time maintains an effect due to a low torque constant during bearing rotation for a long period of time.

The retainer 8 for the ball bearing revolves along the inside of a bearing along with a plurality of rolling elements while rotatably retaining the plurality of rolling elements in the inside of the bearing. The retainer is provided with: a retainer body 8a which has a plurality of pockets 8p rotatably retaining; the plurality of rolling elements one by one and a plurality of protuberances 8t which are formed by partially projecting internal surface Ps of each of the pockets, and also is provided with a water-repellent and oil-repellent film 8b on surface of the retainer body so as to cover at least the plurality of protuberances formed in the internal surface of each of the pockets. In this case, the water-repellent and oil-repellent film is configured to form a metal oxide layer on the surface of the retainer body and to form water-repellent and oil-repellent layer on the surface of the metal oxide layer.