To eliminate a hole machining for roller support from machining of a housing and to reduce a radial size and a manufacturing cost by a method wherein an outer ring is non-rotatably arranged at the housing and a roller revolved through friction contact with the outer ring is rotatably coupled to a low speed shaft.

Rollers 13 and 14 are arranged in a plurality of stages between the sun roller 11 of a high speed shaft 31 and an outer ring 33 concentric therewith. The outer ring 33 is fixed at a housing 41 to support the high speed shaft 31 and the rollers 13 and 14 are revolved. In a so formed transmission, the roller 14 revolved in a state to make friction contact with the inner peripheral surface of the outer ring 33 is rotatably coupled to the support shaft 36 of a low speed shaft 32 coaxial with the high speed shaft 31 and a rotation force is transmitted to the low speed shaft 32 by the revolving roller 14.