To improve the durability by a simple constitution by storing a vane member in a hollow vane chamber having liquid flow holes formed in a fixed or movable vane and formed of a pair of opposite insides opposed in the circumferential direction of a case.

A movable vane 3 defines a vane chamber 6 opened outward in the radial direction and opened in the both sides in the axial direction of a rotary shaft 2 in a vane part extended outward in the radial direction. The vane chamber 6 is provided with liquid flow holes 32, or channels for compressed liquid in the center of a pair of opposite walls 31 in the same positions respectively. A vane member 4 is stored in the vane camber 6, has a rectangular parallelepiped plate body, and provided with a small-diameter orifice 40 or a liquid channel penetrating in the rotation direction of the movable vane 3 in a position coincided with the liquid flow holes 32 of the opposite wall 31. Four through holes 41 with the diameter larger than the orifice 40 are provided in such positions as offset from symmetric to the liquid channel hole 32, one end face in the circumferential direction is set to a projecting face 45 having a plurality of projections, and the other end face is set to a flat surface 46.