Working vehicle comprising a drive system control device , the working vehicle comprising: an engine which is mounted to a travel machine body ; a common rail type fuel injection device which is configured to inject fuel to the engine ; a continuously variable transmission which is configured to shift power from the engine , and a vehicle speed sensor which is configured to detect a vehicle speed of the travel machine body, and a sensor configured to detect a rotating speed (R1) of a main shift output shaft of the continuously variable transmission , wherein when the engine is operating at a first rotating speed on a low speed side, a first engine load rate standing for a rate with respect to the maximum torque at the first rotating speed being more than a predetermined value, in the case where the overload acts on the engine , wherein the drive system control device is configured to change the engine speed to a second rotating speed on a speed side higher than the first rotating speed, such that the rotating speed of the engine and an engine operating point relating to a torque of the engine are changed to a second engine operating point at which an output horsepower equals to that in the case where the overload acts on the engine at a first engine operating point; a second engine load rate at the second rotating speed is set equal to or less than the predetermined value, and wherein the drive system control device is configured to change and regulate a change gear ratio of the continuously variable transmission based on the vehicle speed detected by the vehicle speed sensor and the rotating speed of the main shift output shaft of the continuously variable transmission in such a manner that a vehicle speed of the travel machine body does not change. an engine which is mounted to a travel machine body ; a common rail type fuel injection device which is configured to inject fuel to the engine ; a continuously variable transmission which is configured to shift power from the engine , and a vehicle speed sensor which is configured to detect a vehicle speed of the travel machine body, and a sensor configured to detect a rotating speed (R1) of a main shift output shaft of the continuously variable transmission , wherein when the engine is operating at a first rotating speed on a low speed side, a first engine load rate standing for a rate with respect to the maximum torque at the first rotating speed being more than a predetermined value, in the case where the overload acts on the engine , wherein the drive system control device is configured to change the engine speed to a second rotating speed on a speed side higher than the first rotating speed, such that the rotating speed of the engine and an engine operating point relating to a torque of the engine are changed to a second engine operating point at which an output horsepower equals to that in the case where the overload acts on the engine at a first engine operating point; a second engine load rate at the second rotating speed is set equal to or less than the predetermined value, and wherein the drive system control device is configured to change and regulate a change gear ratio of the continuously variable transmission based on the vehicle speed detected by the vehicle speed sensor and the rotating speed of the main shift output shaft of the continuously variable transmission in such a manner that a vehicle speed of the travel machine body does not change. <EOS>