To provide a continuously variable transmission wherein a driven shaft can be forwardly rotated, stopped and reversely rotated with a prime mover left as rotated, to provide a simple structure transmitting turning force through a plurality of ball rollers further with good accuracy in small size.

In both sides of a casing 1, a prime mover shaft 2 and a driven shaft 3 arranged on a coaxial line are pivotally mounted. In an end part of the driven shaft 3, a driven wheel 4 is provided through a torque cam 5, also a track ring 6 opposed to this driven wheel 4 is fixed to the casing 1. In a side of the driven wheel 4, a prime mover wheel 8 rotated with the prime mover shaft is provided. Five ball rollers 9, provided with an outer ring 10 engaged into press contact with the track ring 6 in one point respectively on a spherical surface between the driven wheel 4 and the prime mover wheel 8, are arranged in a planet shape, a fork-shaped spider 13 turned with a shifter 11 while holding these ball rollers 9 in a fixed space is provided in the prime mover shaft 2, and the outer ring 10 of the ball roller 9 is engaged with a ring-shaped groove 12 provided in the shifter 11.