In the present invention, a shaft torque command value (a command value of T

**12**) is represented as T

**12**
*r*, and the dynamometer torque T

**2** is controlled on a basis of a transfer function expressed by the following equation (4). This equation (4) includes: an integral element having an integral coefficient K

_{I }for integral calculation of a deviation (T

**12**
*r*−T

**12**) between the shaft torque command T

**12**
*r *and the measured shaft torque T

**12**; a differential element having a differential coefficient K

_{D }for differential calculation of the measured shaft torque T

**12** with a first-order delay (time constant f

_{1}); and a proportional element K

_{P }for proportional calculation of the measured shaft torque T

**12** with a first-order delay (time constant f

_{1}). The equation obtains a torque control signal T

**2** by subtracting the differential element and the proportional element from the integral element.