PURPOSE: To easily obtain a highly functional film by forming a liq. phase for development with a nonaqueous solvent, and making the developing solvent more hydrophilic than the solvent in the liq. phase.

CONSTITUTION: Glucose oxidase, urease, alcohol dehydrogenase, tyrosinase, invertase, etc., are used as the film forming compd., and the developing soln. of the film forming compd. is prepared with distilled water as the developing solvent (e.g., water, hydrocarbons, halogenated hydrocarbons, etc.). The soln. is uniformly dropped on the liq. phase (e.g., n-butyl alcohol, etc.), and a monomolecular film is developed. A hydrophilic substrate such as hydrophilic glass is then horizontally held, and approached to the liq. phase surface having the developed film to adhere the film to the substrate. By this method, a highly functional film can be obtained.