To provide a method of modifying surface of a substrate, e.g., glass, to make it water- and oil-repellent by treating the substrate with a silane coupling agent containing no fluorine.

This method of surface modification comprises the steps of (A) treating a substrate having OH group on the surface with a silane coupling agent having at least one type of polar group and silanol group as a hydrolyzate of alkoxysilane group, to fix the polar group on the substrate surface by the reaction between the OH and silanol groups, followed by (B) treating the above substrate with a fluoroalkyl carboxylic acid halide or perfluoropolyoxyalkyl carboxylic acid halide of straight or branched chain, to fix the fluorine- containing group by the reaction between the above polar group and carboxylic acid halide. The component B is preferably a compound shown by the formula Rf(CH2)nCOX (Rf is a 6-20C fluoroalkyl; X is a halogen; and (n) is 0 or 1-10), or the formula RfRfCFCOX (Rf and Rf' are each a 4-18C fluoralkyl or chloroalkenyl).