To provide a load sensing type direct acting continuously variable transmission which can continuously vary deceleration ratio by sensing a load given in accordance with an operating environment corresponding to external force or the like also convert a rotary motion into a linear motion by high transmitting efficiency.

In a screw shaft 2 constituted by screwing helical screw parts 4, 3 having a prescribed pitch P and a nut 1, a diameter D0 of the screw part 3 in the nut 1 is formed a little larger than a diameter d of the screw part 4 of the screw shaft 2 screwed thereto, also the nut 1 is supported turnably relating to a support member 5, this support member 5 is energized by a prescribed spring load Fs in a diametric direction of the screw shaft 2, so as to bring the nut 1 into eccentric contact with the screw shaft 2.