To provide a pump device which can have a high discharge rate even in a high discharge pressure range.

An impeller 16 is provided with first and second stages movable vanes 20, 21, concentric therewith, and the casing 17 side is provided with stationary vanes 22 located between the first and second stage movable vanes 20, 21. When the impeller 16 is rotated, fluid sucked into a casing 17 through an inlet port is subjected to energy caused by a pressure and a speed given by the first stage movable vanes 20, and thereafter, the speed energy is converted into a pressure energy by means of the stationary vanes 22. Further, the fluid is subjected to energy caused by a pressure and a speed given by the second stage movable vanes 21, and accordingly, the pressure of the fluid becomes higher. Further, since the movable vanes 20, 21 are spiral so as to be not orthogonal to the rotating direction of the impeller 16, a load torque which is so high is not exerted to the vanes 20, 21 even though the pressure of the fluid becomes higher. Thus, the tendency of lowering the rotational speed of the impeller 16 is restrained, thereby making it possible to endure a high discharge rate.