PURPOSE: To make construction easy by a method wherein concrete columns are erected on the natural ground, then foundation concrete is placed and U- shape blocks are laid over the concrete, and slabs are fixed to the blocks with anchor bolts.

CONSTITUTION: A slope of the shoulder of a road inclined down from the road toward the bottom of a valley is cut approximately at a right angle to the road surface, and thereby the natural ground serving as a foundation for constructing a road is formed. Then, a plurality of concrete piles 3 are erected on the natural ground at intervals, each of which corresponds to the width of a U-shape block 7 and an upper slab 10. Foundation rubbles 4 are then laid over the natural ground and foundation concrete 5 is cast thereon and at the same time, reinforcements 6 for the piles 3 are arranged. The blocks 7 are laid over the concrete 5, and the bottoms 8 of the blocks 7 are anchored to the concrete 5 with anchor bolts 9. Furthermore, upper slabs 10 are fixed over the blocks 7 with anchor bolts 11.