To enhance the suppression function of engine stalling in a low speed area, and simultaneously avoid excess fuel increase in a intermediate speed area.

By unbalance force between governor force and torque spring force, the pin tip portion 13 of a torque pin 11 is extruded so that only a governor input lever 3 is rocked and a metering rack is metering moved in a torque up area exceeding a rated load area. A torque spring 12 is composed of one pair of front and back springs 12a, 12b, and when the pin tip portion 13 of a torque pin 11 is extruded, in the early stage of extrusion the torque pin 11 is extruded by the resultant force of the respective spring forces. After the elongation of either one spring 12b reaches limit, the pin 11 is extruded by only the spring force of the other spring 12a.