PURPOSE: To perform sheathing work without causing the deformation of sheathing walls and also of the ground's surface by a method in which an anchor-introducing hole is formed in the sheathing wall by inclining it toward the opposite side of the excavation side and an anchor is inserted into the hole.

CONSTITUTION: A pipe 3 for forming an anchor-introducing hole is set in place in a concrete sheathing wall 2 by inclining it downwardly at a given angle in the opposite side of the excavation side, and two concrete sheathing walls are erected to slightly deeper depth than the position of excavation. An anchor 4 is inserted into the hole 3 and penetrated into the substratum 1, the anchor 4 is fixed to the upside of the sheathing walls 2, and the ground 1 on the opposite side is excavated to the position to be excavated.