A high-speed intermittent rotary mechanism which includes two pairs of meshing driving gears and driven gears properly located respectively on driving and driven shafts with equal center-to-center distances. The driving gears are fixed on the driving shaft and the driven gears, which cooperate with an epicyclic train of gears, are pivotally mounted on the driven shaft by means of bearings. One or both pairs of the abovementioned meshing driving and driven gears are cam-shaped to transmit a smooth, accurate and intermittent rotary motion while in high speed operation.