A V-belt type stepless transmission, basically including an input pulley and an output pulley mounted on parallel input and output shafts, respectively, each of the input and output pulleys having a stationary flange and a movable flange axially displaceable relative to the stationary flange and rotatable integrally therewith; an endless V-belt lapped around the input and output pulleys to transmit power therebetween; a servo mechanism for the movable flange, constituted by a drive member having a first screw or a second screw, the first screw formed on the movable flange or on a structure integrally connected to the movable flange, the second screw threadedly engaged with the first screw for axially displacing the movable flange by rotation of the second screw relative to the first screw, and a drive mechanism for the drive member; and a cam mechanism provided at least on one of the input and output shafts to vary compressive belt gripping force of the stationary and movable flanges in proportion to the torque transmitted by the belt.