Abstract: A bicycle drive device is provided. The drive is composed of a ring gear, attached to the rear hub, and a chain wheel fixed on the axle of the rear wheel. The chain wheel is fastened on the outer surface of a unidirectional bearing so as to move in only a clockwise direction. On the inner plane of the chain wheel there are three base axles on which the planet gears are rotatively coupled. A sun gear is coupled to the inner surface of the unidirectional bearing for rotation in only a counter-clockwise direction. These gears mesh properly and form the new drive device. When the pedals are rotated clockwise to make the bicycle move forward, the planet gears would be driven counter-clockwise but are instantly locked by their meshing with the sun gear. This results in a non-interaction gear set and the bicycle would move forward without interference. As a bicycle coasts, with no pedal power input, the ring gear moves clockwise and drives the planet gears to rotate in a clockwise direction.