PURPOSE: To make the control of a torque load easy and accurate and to simplify the structure, by imparting the torque load to samples by a servomotor through a planetary gear mechanism, and controlling the torque load by a control unit.

CONSTITUTION: A torque load is applied by rotating a gear G by a servomotor 54 through a reducer 53. Namely, when the gear G is rotated, an outer sun gear CF and a planetary gear B of a planetary gear mechanism, which is engaged with the gear G, are rotated. At this time, the phase of the planetary gear B and a gear D, which is coupled with the gear B through a carrier 51, is different from the phase of an inner sun gear A. As a result, torsional moment is loaded to samples 10, which are linked to a power circulation system. A control unit 55 controls the torque load by the servomotor 54 based on the signal and the command signal from a torque meter 56. Thus, the control of the torque load becomes easy and accurate for a broad range, and the structure is simplified.