For easier care of a bed-ridden patient, a fold-up wheelchair comprises a chair main body (2) having a back rest, the chair main body being foldable upward and downward; rear frames (6) of the chair main body (2); rear legs (15) extending lower rearward, the rear legs being connected to a vertically middle portion of the rear frames (6) so as to be rotatable forward and rearward; extensible working bodies (16) connected to the rear legs (15) and upper end portions of the rear frames (6) so as to be rotatable forward and backward; a motor (17) operating the respective working bodies (16) so as to expand and contract synchronously, the motor being provided in an upper end portion of the working bodies (16); guides (24) arranged in right and left sides of the chair main body (2) so as to extend forward and backward, front and rear end potions thereof being supported by a pin; a rod (25) fitted to the guide (24) so as to be slidable forward and backward, a rear end portion of the rod (25) being connected to the rear legs (15) in such a manner as to be rotatable forward and backward; and a front wheel (26) and a rear wheel (27) respectively provided in a front lower portion of the chair main body (2) and a lower end portion of the rear legs (15).