An oscillation arm moves in a seesaw fashion about an oscillation axis which is supported by a support rod and which serves as a fulcrum. A rotation arm and a pressurizer are provided on one end of the oscillation arm. One end of the rotation arm is rotatably attached to the oscillation arm, and a load weight is placed on the other end of the rotation arm. By rotating the rotation arm, the magnitude of a force to be applied by the load weight to the pressurizer is adjusted. More specifically, by displacing the load weight to a predetermined position by rotation and then causing the load weight to stop at this position, a static load corresponding to the rotation angle can be applied to the pressurizer. Further, by causing the load weight to perform rotational motion, the magnitude of the force to be applied to the pressurizer is periodically varied, so that a load which varies periodically can be applied to hard tissue.
