PURPOSE: To produce a decorative concrete flat panel having a good shape without contaminating a tile with the concrete creeping to the surface of the tile at the time of the casting of concrete.

CONSTITUTION: In a form 18 having a peripheral wall part 20 and a bottom wall part 22 and having a molding recessed part 24 for casting concrete having the shape corresponding to a concrete substrate, at least the bottom wall part 22 is molded in such a state that the bottom wall part is integrated with a tile 14 and the rear surface of the tile 14 constitutes the bottom surface of the molding recessed part 24 and a resin material is closely bonded to the surface and side end surfaces of the tile so as to cover them by the molding of the resin material. Flowable concrete is cast in the molding recessed part 24 of the form 18 to be integrally solidified along with the tile 14 and the resin part of the form 18 is removed.