In this process for producing a fluorine-containing sulfonylimide compound, a process for producing a fluorine-containing sulfonylimide compound ((Rf1SO2)(Rf2SO2)2N.M) is employed that comprises a first step of obtaining a reaction liquid by reacting a perfluoroalkylsulfonyl fluoride (Rf1SO2F) with ammonia, a second step of obtaining a mixture containing an alkaline metal salt of a perfluoroalkylsulfonamide (Rf'SO2NH.M) by reacting the reaction liquid with at least one type of alkaline metal compound selected from among hydroxides, carbonates and bicarbonates of alkaline metals M of either Li, Na or K, and a third step of reacting the mixture with a perfluoroalkylsulfonyl halide (Rf2SO2X), wherein Rf1 and Rf2 represent linear or branched perfluoroalkyl groups having 1 to 4 carbon atoms, and X represents fluorine or chlorine.