To obtain a coating agent composition for providing a coating film having excellent stain resistance, especially exhibiting excellent stain prevention of oil stain by dissolving a specific perfluoropolyether-modified aminosilane and/or its partially hydrolyzed condensate in a fluorine-modified solvent.

This composition comprises (A) a perfluoropolyether-modified aminosilane of formula I (X is a hydrolyzable group; R1 is a monofunctional hydrocarbon; R2 is H or a monofunctional hydrocarbon; Q is an alkylene; m is 6-50; n is 2 or 3; x and Y are each 1-3) and/or its partially hydrolyzed condensate and (B) a fluorine-modified solvent. A perfluoropolyether-modified aminosilane of formula II is preferable among the aminosilane of formula I and/or its partially hydrolyzed condensate as the component A. m-Xylene hexafluoride, etc., are preferably as the component B. The concentration of the component A in the composition is preferably 0.2-20 wt.%. When an article is treated with the composition, preferably the reaction is promoted under moisture.