To provide a swinging vane motor as improvement of the conventional technique represented by many sorts of fluid pressure motors of such a type as rotated by a pressure fluid and obtaining a torque, capable of meeting the important requirements that the fluid pressure receiving area of each vane is large, that the initial motion of the vane is certain and stable owing to no use of spring action etc., and that the fluid pressure receiving area of the vane remains constant in generating the torque.

The swinging vane motor has vanes and a rotor divided in four equal segments, and is arranged so that one edge member of the vane constituting the pressure receiving area is formed with the peripheral circumferential length of the rotor segment and the center of a cylindrical casing is positioned identical to the axis of the rotor, whereby the pressure receiving area of the vane moving in rotation is made larger and constant, which allows establishing a structure able to supply the fluid always from behind the vane.