A water- and oil-repellent agent is produced by subjecting (a) a polyfluoroalkyl group-containing (meth)acrylate and (b) a fluorine atom-free polymerizable monomer to an emulsification treatment in the presence of (c) a polyethylene oxide adduct type, cationic surfactant, or both of the cationic surfactant and a polyethylene oxide adduct type, non-ionic surfactant, and (d) a glycol-based compound, followed by copolymerization reaction in the presence of a polymerization initiator, and admixing the resulting aqueous dispersion with (e) a blocked isocyanate, and gives a satisfactory water and oil repellency to not only synthetic fibers, but also natural fibers, and also has a distinguished washing durability.