At least one monomolecule film is formed on a transparent substrate surface directly or via a protective film. The monomolecule film is formed with chemical coupling of chlorosilane surface active compound, for example, of the formula: F(CF2)m(CH2)nSiRqX3—q where m is an integer of from 1 to 15, n is an integer of from 0 to 15 provided that the total of m and n is an integer of from 10 to 30 and R is an alkyl or an alkoxyl group, or F(CF2)m′(CH2)n′A(CH2)pSiRqX3−q where m represents an integer ranging from 1 to 8, n′ represents an integer ranging from 0 to 2, p represents an integer ranging from 5 to 25, q represents an integer ranging from 0 to 2, X represents a halogen atom or an alkoxyl group, R represents an alkyl or an alkoxyl group, and A represents —O—, a —COO— or —Si(CH3)2—. The transparent substrate such as glass is made hydrophobic and free of contamination.