An axially movable ball bearing includes a cage having a plurality of circumferentially distributed guideways, each guideway including first and second axially extending channels joined at their ends by semi-circular sections. A plurality of balls are provided in each of the guideways. The first channels are open radially inwardly so that the balls therein may engage a shaft along which the bearing is adapted to move. A thin-walled metal housing is tightly fitted over the cage, and has bridge sections aligned with the first channels. The bridge sections have on their radially inner surfaces, guide courses for engaging the balls in the first channels. The housing is slotted between the bridge sections, so that the second channels project radially outwardly between the bridge sections. The bridge sections are joined together at each axial end of the bearing by end rings. The metal housing has a greater hardness in the region of the courses of the bridge sections than in the other regions thereof.