It is an object of the present invention to provide an assistance device that can further reduce the burden on the person being assisted in assisting the sitting operation. In the operation process of the seating operation by the assistance device (1), the central axis (due to the lowering of the elevating part (30) rather than the rearward movement amount (Nb) of the reference position (Ps) accompanying the backward turning of the swing part (40) ( A lowering step of lowering the support member (50) from the start position of the seating operation by coordinating the operations of the elevating unit (30) and the swinging unit (40) so that the downward movement amount (Nd1) of A) is increased. And, after the descending step, at least the swinging portion (40) is rotated backward to retract the supporting member (50) to the end position of the seating operation.着座動作の補助の際の被介助者の負担をより軽減することができる介助装置を提供することを目的とする。 介助装置（１）による着座動作の動作処理には、揺動部（４０）の後旋回に伴う基準位置（Ｐｓ）の後方移動量（Ｎｂ）よりも昇降部（３０）の下降による中心軸（Ａ）の下方移動量（Ｎｄ１）が大きくなるように昇降部（３０）および揺動部（４０）の各動作を協調させて、着座動作の開始位置から支持部材（５０）を下降させる下降工程と、下降工程の後に、少なくとも揺動部（４０）を後旋回させて、着座動作の終了位置まで支持部材（５０）を後退させる後退工程と、が含まれる。
