To perform pumping of underground water only from an aquifer present below in a state that a communication state between a well pipe and the aquifer formed above is disconnected through closing of a water intake valve by connecting a water intake pipe to the well pipe through a water intake valve.

A pumping device 13 is formed such that an impervious material 20 to cut off water by vertically partitioning an excavated hole 5 in a position of an impermeable layer 1 and a well pipe 15 provided with a water injection screen 14 in a position extending through the impervious material 20 and fronting on a water injection layer 3 are arranged in an excavated hole 5 extending through the impermeable layer 1 to the water injection layer 3. A pump 18 and a packer 22 are disposed in the well pipe 15 and further, a water intake pipe 17 having an water intake screen 16 in a position fronting on the water intake layer 2 and a lower end connected in the position of the impermeable layer 1 to the well pipe 15 through a water intake valve 21 is arranged in juxtaposition in the well pipe 15.