Abstract: A gear ratio is controlled to infinity so as to allow a vehicle to get underway smoothly with a hydrostatic continuously variable transmission equipped with a hydraulic pump having a cam plate with a fixed angle of inclination and a hydraulic motor having a cam plate with a variable angle of inclination. First distributing valves allow the cylinder holes of a hydraulic pump to selectively communicate with a low pressure oil circuit and high pressure oil circuit are operated by a first eccentric ring located in an eccentric weight ring. The eccentric weight ring rotates along with an input cylinder shaft and moves as a result of centrifugal force in a direction tilted 45.degree. with respect to an imaginary trunnion line O.sub.1 of the hydraulic pump so that the phase in the direction of eccentricity of the first eccentric ring is automatically changed. The first eccentric ring is off center in the direction perpendicular to the imaginary trunnion line O.sub.