PURPOSE: To provide a water-repellent treating agent enhancing the adhesivity between a water-repellent film and the surface of a treated member for improving the durability of the water-repellent film.

CONSTITUTION: A water-repellent agent comprising a mixture of grinding particles with a water-repellent solution containing a silicone-based water- repellent agent is coated on the surface of a glass plate and subsequently cured to form a cured film adhesively bonded to the surface of the glass plate. The grinding particles remaining in the cured film are wiped off to form a water- repellent film. Since harmful substances are polished off and simultaneously the water-repellent agent is coated on the surface of the glass plate, the silicone- based water-repellent agent is surely reacted with silanol groups on the surface of the glass plate to enhance the adhesivity therebetween.