To solve the problems of leading to eccentricity of an outer ring such as a drum, reduction in transmission efficiency, generation of vibration, seizure of a roller uncontributing to the transmission and reduction in the service lift of a bearing, since rotary power can be transmitted only by two intermediate rollers in a load state when one intermediate roller does not contribute to the transmission, when the small two intermediate rollers become inverse in the biting-in direction as a wedge, since the drum is eccentrically arranged on an input shaft (a high speed shaft) in a conventional traction type transmission having a wedge roller.

This transmission has the high speed shaft and a low speed shaft rotatably supported in a casing, and is composed of a ring member concentrically arranged with the high speed shaft and a plurality of intermediate rollers abutting on the periphery of the high speed shaft. The transmission shifts a speed by transmitting any of rotation of the ring member and revolution of the intermediate rollers to the low speeds shaft. The wedge roller made to bite in the same direction is respectively interposed between the ring member and the respective intermediate rollers.