Provided is a method of fixing an antibacterial agent whereby excellent antibacterial properties and sustention of the same can be imparted to articles comprising materials over a wide scope. A method of fixing an antibacterial agent characterized by comprising: subjecting the surface of an article to a surface-treatment whereby an oxygen-containing functional group is imparted thereto and (a) treating the article by using an antibacterial composition which comprises a silicon-containing compound represented by general formula (1), wherein R1 represents a hydrocarbon group having 6 or more carbon atoms, R2 and R3 may be either the same or different and each represents a lower hydrocarbon group, R4 represents a divalent lower hydrocarbon group, R5, R6 and R7 may be either the same or different and each represents a lower alkyl group or a lower alkoxy group, and X represents a halogen ion or an organic carboxyloxy ion, or treating the same with the above-described antibacterial composition followed by microwave irradiation at 1 to 10 GHz while allowing the antibacterial composition as described above to remain on the surface of the article.
