to the air cylinder 22 is provided with a regulator unit 28 for compressed air composed of an air filter a pressure regulator and lubricator an air microvalve 29 is incorporated as a switching means between the air cylinder 22 and the regulator unit 28 and is operated by the transverse movement of the knee lever 6 for raising and lowering the presser foot 4 the presser foot 4 and the movable cantilever member 12 are moved up and down at the same time by a single action of the knee lever 6 with the knee at the same time the air supply to the air cylinder 22 is interrupted to raise the movable cantilever member 12 away from the fixed cantilever member 11 when the air microvalve 29 is operated with the movement of the knee lever 6 to raise the presser foot 4 as pushed by the knee alternatively a foot switch may be provided separately for the control of air supply to the air cylinder 22 independently of the knee lever 6 in place of the air microvalve 29 it is of course optional for controlling the movement of the movable cantilever member 13 to utilize the power for driving the sewing machine 2 per se or to connect the movable cantilever member 12 directly to.