Abstract: A stepless speed change gear has an axially movable speed changing ring that is frictionally engaged with a plurality of conical rollers. The stepless gear has improved durability and reduced weight due to a flat annular power transmitting surface and an annular power transmitting surface of arcuate cross-sectional contour on the bottom portion of each conical roller. A force caused by a contact pressure generating device is applied to the conical rollers at the annular power transmitting surface of arcuate cross-sectional contour, so as to advance the conical rollers into a space between the speed changing ring and another frictionally engaging member as a wedge so that required contact pressures are applied on the frictionally engaging points.