Intentions of a user are read from movements of the joints of the user without the use of a myoelectric sensor, and a force to support motions of the user is generated.Even if there is friction that is difficult to model in a gear portion of a joint actuator, the friction is compensated for, and joint units are controlled to follow an idealized mathematical model. In this manner, the force to support motions is generated, without giving any uncomfortable feeling to the joints of the user wearing the device. When motions of the user are supported, a mathematically-determined torque is applied to the joint units, so that a natural supporting force is constantly provided to the user in various circumstances.