A continuous V-belt transmission comprising: a primary pulley and a secondary pulley individually including two sheaves supported on shafts and made axially movable relative to each other; a belt made to run on the two pulleys; mechanical actuators individually including first members and second members for moving the movable sheaves of the two pulleys on the basis of the relative rotations of the two members: and pressure regulating mechanisms for applying an axial force corresponding to a transmission torque to at least one of the pulleys. In an unshifted state, the rotations of the pulleys are transmitted from the externally threaded portions integrated with the movable sheaves to the carriers of the planetary gear mechanisms so that they are transmitted through the ring gears to toe internally threaded portions on the basis of the sun gears being stopped. At this time, the externally threaded portions and the internally threaded portions are rotated integrally with the pulleys at the same r.p.m. If the sun gears are rotated through the shafts by the shift motor, the externally threaded portions and the internally threaded portions are rotated relative to each other to effect the shifting operation. At this time, the stroke of a ball screw unit is caused to match the stroke of the movable sheaves by non-circular gears.