PURPOSE: To facilitate tunneling work by drilling plural holes forwardly and diagonally downwardly from tread in front of a working face, and inserting a slit type straigner into the drilled holes, and connecting a well point pump to the strainer to pump water.

CONSTITUTION: A slit type strainer 2 is formed by arranging fifteen axial slits 3 of width about 2 mm and length about 150 mm in a steel pipe of diameter about 76 mm and length about 2.75 m, in their respective positions decided by dividing the circumference of the pipe into five parts. A plurality of holes are drilled by a bowling machine in the ground ahead of an diagonally downwardly from a tread in front of a working face 1 and the slit type strainer 2 is inserted into the drilled holes and a well point pump is connected to the strainer to continuously dump water. Thus installation of a well point is facilitated and also water is efficiently pumped without causing blinding even when the natural ground is made up of the sand.