PURPOSE: To provide efficient pump action under various conditions by piping a suction pipe separately from a suction port of a submerged pump body near a injection position of a jet nozzle.

CONSTITUTION: A sub-merged pump body 1 is provided on the lower portion with a pump suction port 2 and on the body side with a discharge pipe 3 to which is connected a jet pump 4. The jet pump 4 is connected to a pumping-up pipe 6 connected with one or a plurality of suction pipes having one end opened to the side of the pump body 1, such that the direction of jet injection is aligned with the axis of the pumping-up pipe 6. An injection nozzle 7 is connected to the pumping-up pipe 6 through a protective pipe 8 having a diameter smaller than the bore of the pumping-up pipe, and an air introducing pipe 9 is piped to the protective pipe 8.