PURPOSE: To produce a board for surface constitution of a footway, etc., which does not fade and is strong by combining a thick board of water permeable concrete formed by using aggregate and cement and a thin sheet of water permeable natural stone formed by using crushed stone of natural stone and rigid plastic.

CONSTITUTION: After a mixture composed of the aggregate 1 such as crushed stone, the cement 2 and water are packed into a form, the mixture is pressed to form a thick layer 4 of the water permeable ready mixed concrete dispersed with gaps 3 between the aggregate 1 materials. The mixture composed of the crushed stone 5 of the natural stone and the rigid plastic binder 6 is imposed on the surface of this thick layer 4 and is pressed to form the thin layer of the water permeable natural stone 8. The mixture composed of the plastic binder in the thin layer 8 is simultaneously force-fed into the gaps 3 of the thick layer 4 to integrally bind the layers 4, 8, by which the water permeable natural color flat board is obtd. This flat board does not fade even after long- period use and since the board has the thin layer 8, the board has the high strength; further, the layer 8 is thin and, therefore, the cost is low.