PURPOSE: To easily secure sufficient film thickness by pouring a slurry to a gap arranged between the surface of a base material to be coated and a thin film, immersing a material capable of curing a binder in the slurry into the slurry to form a coating film and then hardening the coating film.

CONSTITUTION: At the time of applying the slurry 3, a thin film 4 capable of permeating the material for curing the binder in the slurry 3 is arranged with spacers 2 for forming a gap equivalent to the slurry coating thickness between the surface of the base material 1 to be coated near the surface of the base material 1 to be coated with the slurry and after that, the slurry 3 is poured into the gap. The slurry 3 is preliminarily stuck to the surface of the maternal to be coated to form the coating film by immersing the material for curing the binder with the thin film 4 in the slurry 3. Successively the coating film is hardened. In this case, water glass is used as the binder and the material for curing the binder is an alcohol.