PROBLEM TO BE SOLVED: To provide a small and lightweight stand-up assist device facilitating installation thereof on a wheelchair and furniture and having a high versatility.SOLUTION: The stand-up assist device includes a torsion coil spring 6b, a double torsion spring 6a, and a gas spring 4 between a seating face 1 and a pedestal 2 that are openably/closably joined via a hinge 3, and the seating face 1 is inclined by lifting the rear part of the seating face 1. At least two torsional coil springs 6b and double torsion springs 6a are aligned on a straight line in a direction perpendicular to a rotary shaft of the hinge 3. Consequently, force pushing up the seating face 1 is maximized at an initial period of a stand-up movement and minimized at a period of ending the stand-up movement so as to enable smooth and safe stand-up and sit-down movements.
