An impeller 31 is provided with a rotating shaft rotatably supported at the upper and lower ends thereof by an upper bearing 9 and a lower bearing 10, a plurality of vanes 32 connected to the rotating shaft on the inner circumferential edge side thereof, an annular coupling portion 8 connecting outer circumferential edges of the vanes, and driven magnet portions 12 provided in a lower portion of the annular coupling portion. The rotation of a rotor is transmitted to the impeller through magnetic coupling between the driven magnets 12 and drive magnets 16 provided to the rotor 13. The upper edge of each of the vanes has a bend point, and an angle ± formed by a peripheral upper vane edge 33a and an angle ² formed by a central upper vane edge relative to the downward direction of the rotating shaft are both acute angles and have a relationship of ± < ². An inner wall surface of a housing in a region opposed to the upper edge of the vane has a shape following the upper edge of the vane. In a configuration in which the rotating shaft of the impeller is supported by the upper and lower bearings, the effect of cleaning by a blood stream in the vicinity of the upper bearing is obtained sufficiently.
