To provide a wheelchair or a chair for self-standing, which can achieve the reduction of a caring labor for a patient who uses the chair, an effective rehabilitation and the shortening of a recovery period by the effective rehabilitation, and also, the reduction of an economical burden accompanying the shortening of the recovery period.

On a chair structure S for which a supporting frame 3 supported by a front wheel 1 and rear wheels 2, a seat-supporting frame 4, a strut frame 8 equipped with an arm rest section 6 and a push handle 7 are integrated by a connecting means, a standing- seating assisting means T, i.e., an axillary crutch-form underarm section supporting body 10 equipped with an underarm section support arm 9 which is connected to the upper end portion in a manner to be fixed or horizontally held, is made vertically movable, and on the vertically movable side, a backrest 5 is attached, and the rear end portion of a seat 11, of which the front end portion is rockably and slidably supported by the seat supporting frame 4, is connected, and at the same time, a mechanism wherein the base end portion of a foot supporting arm 13 on the free end portion of which, a foot placing base 12 is disposed, and the lower end portion of the vertically movable underarm supporting body 10, are integrally swung around the horizontal axis, is supported, and manually or by an electric force, reversible motions of a seating posture and a standing posture of a patient are assisted.