A holding structure, such as a manipulator, includes a plurality fingers. At least one of the fingers is movable such that an object can be held or released by a closing or opening motion of the movable finger. At least one contact surface of the fingers, which is capable of being brought into contact with the object, is formed by an elastic member, and at least one elastic member is adapted to reversibly change its elasticity under the control of an external supply of energy to the elastic member.