A belt-driven continuously variable transmission having a downsized torque cam assembly for creating forward thrust to push a movable sheave toward a fixed sheave.The belt-driven continuously variable transmission is adapted to output a torque while changing a speed ratio continuously by altering an effective diameter position of a driving belt. The belt-driven continuously variable transmission is comprised of: an output gear, which is fitted onto the rotary shaft of the driven pulley to output the torque while being allowed to rotate relatively; a piston, which is fitted onto the rotary shaft of the driven pulley between the movable sheave and the output gear while being allowed to rotate integrally with the movable sheave and to reciprocate in an axial direction of the rotary shaft, and which increases an internal pressure of the hydraulic chamber by moving toward the movable sheave; and a torque cam assembly, which is interposed between the piston and the output gear, and which pushes the piston toward the movable sheave when the torque transmitted through the driven pulley is increased.