PROBLEM TO BE SOLVED: To obtain an excellent surfactant composition comprising mixtures of the polymers containing perfluoroalkyl groups. SOLUTION: The surfactant composition is obtained by addition or polymerization, subsequently by subjecting to treatment with thiol, an amine, and the like, of the monomer unit represented by the formula Rfsb-Z (wherein Rf is a perfluroalkyl group; (s) is a linear chain; (b) is a branched chain; and Z is a double bond, a polymerizing group such as an epoxy group, or the like).