PURPOSE: To reduce the construction cost and effectively utilize the land by driving a pile in a boarder and installing sheathing boards in such a manner that their horizontal parts are put on the upper end of a pile.

CONSTITUTION: For example, there is prepared a concrete-made pile 12 whose cross section is 80mm×100mm and which is 750mm long. Then, a plurality of piles 12 are driven under-ground along a boarder line between a field path 10 and a field 11 at a specified span (such as 2000mm). On the other hand, there is prepared a sheathing board 13, which is 130mm wide in the horizontal area and 300mm high in the vertical area, for example. Then, the horizontal part 14 is loaded on the upper surface of the pile 12 exposed on the ground surface. At the same time, the vertical part 15 is directed at the field path 10 so that the sheathing board 13 is buried underground. The horizontal area of the sheathing board is used as a side walk, thereby effectively utilizing the sheathing board.