To provide a method of manufacturing a perfluoroalkyl sulfonic acid metal salt, capable of simply and safely generating the perfluoroalkyl sulfonic acid metal salt with a very small amount of impurities and high purity.

A method of manufacturing a perfluoroalkyl sulfonic acid metal salt including a process of obtaining a perfluoroalkyl sulfonic acid solution by mixing the perfluoroalkyl sulfonic acid metal salt represented by the chemical formula (C_nF_2n+1SO₃)_m M₁ and hydrochloric acid in an organic solvent, separating and eliminating a precipitated metal chloride M₁Cl by a filtration, and concentrating the resultant filtrate to eliminate the organic solvent and a non-reacting hydrochloric acid, and a process of obtaining the perfluoroalkyl sulfonic acid metal salt represented by the chemical formula (C_nF_2n+1SO₃)_l M₂, where M₂≠M₁ by reacting the perfluoroalkyl sulfonic acid solution and a metalhydroxide or metal carbonates.