PURPOSE: To form a coating film having excellent electrical characteristics such as a dielectric constant and a dissipation factor on electronic parts by converting a coating composition comprising a hydrogen silsesquioxane resin and a filler coated on a substrate to a ceramic coating film by heating under specified conditions.

CONSTITUTION: After a substrate is coated with a fluid mixture comprising a solvent, a hydrogen silsesquioxane resin and a filler by spray, dip, flow or rotary coating, the solvent is vaporized to form a coating film. Subsequently, the coated substrate is heated at 50-1000°C for ≤3 hours in such an atmosphere as air, oxygen, oxygen plasma, inert gas, ammonia and amine, and the coating film is converted to a ceramic coating film.