Abstract: The inventive ball-bearing planetary gear comprises three coaxial cylindrical ferrules (2,3,4), one of which is fixed. Working slots (5 and 6) and return slots (7,8) are embodied on the internal (4) and external (2) ferrules. Open slots (9) are embodied on the intermediate ferrule (3). The balls (10) are arranged in the open slots and interact with the slots of the ferrules (2 and 4). The first embodiment relates to the relation between the spiral working slots (5) and spiral return slots (7), which are embodied on the internal ferrule (4). The second embodiment relates to a multirow gear. The third embodiment relates to a gear provided with linings (23) in the saddles (24) of which the balls (10) are arranged.