The assistance device includes a base, a pair of left and right core members having linear portions that can enter the left and right sides of the body of the person being assisted, and an outer periphery of the linear portion of the core member so as to cover the person being assisted And an outer peripheral member that is rotatably provided with respect to the linear portion, and is capable of moving relative to the base while supporting the left and right sides of the person being assisted A possible side support part, and a drive part for driving the side support part.介助装置は、基台と、被介助者の胴体の左右の脇に進入可能な直線状部分をもつ左右一対の芯部材と、前記芯部材の前記直線状部分の外周を覆って前記被介助者の前記胴体に接触するとともに、前記直線状部分に対して回転可能に設けられる外周部材と、を有し、前記被介助者の左右の前記脇を支持しつつ前記基台に対する相対的な移動が可能な脇支持部と、前記脇支持部を駆動する駆動部と、を備える。
