To provide a small-sized friction roller type transmission capable of supporting certainly intermediate rollers in a freely rotatable manner and possessed of a lowered speed reducing ratio.

A housing 1 comprises a center roller 2 supported by a ball bearing 3 in a freely rotatable manner, and an outer ring 4 provided eccentrically in the center roller 2. The intermediate rollers 5a 5c integrated with supporting shafts 6a 6c are interposed between the center roller 2 and the outer ring 4. Both ends of the supporting shafts 6a 6c are supported by ball bearings 7a 7c in a freely rotatable manner. Respective external diameters of the ball bearings are made to be smaller than those of the intermediate rollers corresponding to the ball bearings.