Abstract: A transmitting unit which uses bearings and the eccentric principle to reduce or increase the rotational speed. An eccentric portion is integrally formed with an input shaft, and a bearing is assembled along the outer periphery of the eccentric portion. The bearing is eccentrically moved when the input shaft is rotated. The bearing is surrounded by an integrally formed transmitting race, and plurality of radial holes are formed in the transmitting race. The same plurality of transmitting rods are respectively inserted into the radial holes of the transmitting race. An integrally formed outer race surrounds the outer periphery of the transmitting race, and has a plurality of wave grooves on the inner periphery thereof. The same plurality of balls are respectively provided between the transmitting rods and the wave grooves. According to the transmitting unit, the strength of the unit can increase as the unit can be minimized, while the noise and the vibration of the unit can decrease.