To collect the underground water in the artesian inactive state by removing the excavation water by the continuous collecting method, then repeatedly collecting water by the batch collecting method, lifting or lowering a water collecting unit in a casing pipe, and fitting or removing it to or from a packer system in a hole.

Multiple pipes are connected by screws, and a casing pipe 4 is extended to the prescribed depth in a drilled test boring hole. An upper packer 7 and a lower packer 9 are fitted at the tip section of the pipe 4. When an intra-hole system and a packer system are connected, a recessed connecting coupler and a projected connecting coupler 6 are connected to form a packer circuit and a drain circuit. The upper packer 7 and the lower packer 9 are expanded by the control from a surface section, the water collection zone is limited in the test boring hole, the mixed water of the excavation water existing in this zone and the water at the other depth is discharged to the surface or the place other than the water collection zone by the bidirectional pump of a drain unit, and the underground water is quickly substituted by stratum water. After the underground water in the water collection zone is substituted by the stratum water, the stratum water is recovered to the surface by a completely sealed water collecting container stored in a water collecting unit in the artesian inactive state.