A gravitation dynamo comprises a generation unit, holder and output unit. The generation unit includes two supporting wheels, a main shaft, two up and down guiding stay bars, roller chain and several breaking balls of same weight posited in the roller chain evenly. The supporting wheel is rotating linked to the shaft, and the guiding stay bars are fixed in between the two supporting wheels. Along the inner circle of the wheel installed stay bars for the chains. A circle segment rail between the wheels is formed be the stay bars and the guiding stay bars. The segment is totally covered by roller chain. One end of the guiding stay rod is fixed to the shaft; the other end is fixed to the segment end point. To the out end of the guiding stay rod fixed a rotatable guiding roller. The guiding teeth to the side of the roller joggle with the roller chain. The main shaft is fixed to the holder. A chock controlling plate to make the stay rods moving axially is fixed to the shaft on the position corresponding to the roller. One end of the output unit is fixed to the holder and rotating jointed to the main shaft, the other end is linked to dynamo.