PURPOSE: To reduce noise by providing a roller for transferring a torque from one input shaft to at least one of output shafts and a pressure ring disposed in a manner that the pressure ring presses the roller to a radius direction and pushes the roller to the input shaft.

CONSTITUTION: A radius of a cylinder 9 is made r, an inner radius of a pressure ring 12 is R. When a driving torque is transferred from a shaft 8 and the cylinder 9, this mechanism works as a reducing speed mechanism. When a radial compressing force is affected on the roller 11 by the ring 12, the radial compressing force is tangentially worked on a surface of the cylinder 9. The driving torque is transferred from the cylinder 9 to the roller 11, from the roller to the pressure ring 12, and at least through a stud 14 and an arm 16 to an output shaft 13 at a reducing speed ratio r/R. When the shaft 13 is used as an input shaft, this mechanism works as a multiplying speed mechanism of which multiplying speed ratio is r/R. This mechanism is quiet because this mechanism has only a rolling friction and does not have a sliding friction.