A self-sucking centrifugal pump capable of displaying excellent self-sucking and pumping performance without changing the shape of a volute type centrifugal pump which already has a nearly perfect shape. The basic principle of a self-suction operation in which a gas-water mixture is pumped by a vortex current generated in a vane wheel by circulating self-sucking water by utilizing the characteristics of larger and smaller volute chambers formed in an outer circumferential portion of the vane wheel is clearly disclosed in Japanese Patent Publication No. 3039/1953 entitled "Double Volute Chamber Type Centrifugal Pump". In a conventional centrifugal pump of this kind, those skilled in the art were intent on supporting a tail portion of a whirlwind type hollow, which occurs due to a self-suction swirl current for the gas-water centrifugal separation, on a limited part, and could not solve the new derivative technical problems. The present invention has first solved the technical problems definitely by forming in an upper portion of a self-suction water separating chamber e a helical guide flow passage F extending in the direction in which a rising part of a liquid surface occurring due to the centrifugal force of a self-section swirl current is wound down; forming in a bottom portion E of the separating chamber e a wind-out flow passage d extending in the direction in which an outer circumferential portion of the self-suction swirl current is introduced preferentially into a larger volute chamber v2; and forming in a cylindrical wall surface at a lower portion of the separating chamber e a helical guide flow passage G extending in the direction in which an outer circumferential portion of the self-suction swirl current is introduced preferentially into the larger volute chamber v2, the present invention having obtained a self-section type centrifugal pump capable of sending a set current advantageous for a subsequent stage to the same stage.