PURPOSE: To make it possible to stably perform running resistance control having a good response characteristic even when quantity of equivalent inertia is large, by obtaining a speed order value by integrating the deviation of set running resistance torque and the generation torque of an electric dynamometer.

CONSTITUTION: In running resistance control imparting load equivalent to that at the time of running to the engine for vehicle, a resistance constant setting circuit 5 outputs the signal proportional to steady running resistance torque. A differentiation circuit 6 and an inertia constant setting circuit 21 output the signal proportional to the torque generated by the rotary part of an electric dynamometer 2 when the rotary speed of an engine 1 to be tested changed. By these circuits 5, 6, 21, a running resistance setting circuit 25, wherein the rotary part of the dynamometer 2 contains torque compensation generated by the change in the rotary speed of the engine 1 to be tested, is constituted. An integration circuit 22 and the inertia resistance constant setting circuit 23 of a car output the signal proportional to the rotary speed. Then, the outputs of the circuits 5, 21 are compared by comparators 18, 19 and the deviation between them is integrated by an integrator 22 while the integrated output is used as a speed order signal through the circuit 23.