PURPOSE: To construct a water shielding wall effectively and economically by providing a water impervious membrane to the water shielding wall constructed underground.

CONSTITUTION: A pit 1 is excavated, and then two partition plates 5 whose center is fixed with a supporting pole 4 with a groove 3 are inserted vertically into the left- and right-hand end portions of the pit 1 and fixed in parallel inside the pit 1. And, A water impervious film 2, e.g., nylon sheet, etc., is delivered in the neighborhood of the pit 1 and then a plate 6 is attached to its side edge. The water impervious film 2 and the plate 6 are erected together with an angle 7, etc., the water impervious film 2 is positioned in the groove 3 of the supporting ple 4, the plate 6 and the angle 7 are inserted into the supporting poles 4 from above and fixed. Then back-filling materials 12 and 13 are driven into the surface and back sides of the water impervious film 2 to construct a water shielding wall.