PURPOSE: To provide a storage pump device the operating condition of which can easily be switched over between low water level requiring high pumping head and high water level requiring no high pumping head, and also requires a small space for installing the pump device.

CONSTITUTION: A storage pump device includes an inner shaft 4 and an outer shaft 5 each of which can be independently driven. The inner shaft 4 is provided with a lower stage pump 6, and the outer shaft 5 is provided with an upper stage pump 7. The discharge port 8 of the lower stage pump 6 is communicated with the inlet port 9 of the upper stage pump 7. The inlet port 10 of the lower stage pump 6 is communicated with the intake port 2 of a water suction tank 1, and a discharge tank 12 is communicated with the discharge port 11 of the upper stage pump 7.