Provided is a seating assistance tool which is suitable for both a non-handicapped person and a handicapped person, and, even though the pelvis is in an inclined position at the time of seating, enables the inclined position to be maintained comfortably over a long period. A seating assistance tool (1) is provided with an exterior body (2) composed of a back surface part (3) and a seat surface part (4), and a cushion (7) on the seat surface part (4) side, and is used while the seat surface part (4) of the exterior body (2) is mounted on a chair or wheelchair having a back support part. The seating assistance tool is characterized in that the cushion (7) has a thickness gradually increasing from the rear of the seat surface part (4) toward the center of the seat surface part (4) and is provided with an inclined surface (9) formed by gradually elevating the upper flat surface of the seat surface thereof from the rear of the seat surface part (4) toward the center thereof, and the exterior body (2) supports the back surface and seated surface of a seated person by hanging the back surface part (3) thereof from the top of the back support part of the chair of wheelchair.
