The fiber treatment agent of the present invention is characterized in that it contains components A, B, and C, and the content of the antibacterial agent of component B is 4 ppm or more. Component A is a silicone graft polymer, which has a silicone bond-containing main chain and side chains with a molecular weight of 800 or more, and an IOB value of 0.7 or more. Component B is an antibacterial agent, and component C is an organic solvent. As the antibacterial agent of component B, piroctone ethanolamine is preferred. The ratio of the IOB value of the silicone graft polymer of component A to the IOB value of the antibacterial agent of component B is preferably 0.4 or more and 3.0 or less.本發明之纖維處理劑之特徵在於：含有成分A、B及C，且成分B之抗菌劑之含量為4 ppm以上。成分A為矽酮接枝聚合物，其具有含矽氧烷鍵之主鏈與分子量800以上之側鏈，且IOB值為0.7以上。成分B為抗菌劑，成分C為有機溶劑。作為成分B之抗菌劑，較佳為吡羅克酮乙醇胺。成分A之矽酮接枝聚合物之IOB值與成分B之抗菌劑之IOB值的比率以前者/後者計較佳為0.4以上3.0以下。
