A motion assisting device or the like, wherein the asymmetry degree of the motion patterns of human limbs is evaluated according to the variation patterns of the values of a pair of posture variables which vary with the postures in the respective same locations of the limbs. Furthermore, the evaluation result of the degree of the asymmetry can be utilized as the foundation of the motion control of the actuator of the motion assisting device. As a result, the motion of the human limbs can be assisted by the motion assisting device in such a manner that the balance of the motion patterns of the limbs is adjusted.