The present invention provides a process whereby fluorine atom-containing sulfonyl fluoride compound(s) useful as e.g. materials for ion-exchange membranes, can be produced efficiently and at low cost without structural limitations while solving the difficulties in production. Namely, the present invention provides a process which comprises reacting XSO.sub.2R.sup.A-E.sup.1 (1) with R.sup.B-E.sup.2 (2) to form XSO.sub.2R.sup.A-E-R.sup.B (3), then reacting (3) with fluorine in a liquid phase to form FSO.sub.2R.sup.AF-E.sup.F-R.sup.BF (4), and further, decomposing the compound to obtain FSO.sub.2R.sup.AF-E.sup.F1 (5), wherein R.sup.A is a bivalent organic group, E.sup.1 is a monovalent reactive group, R.sup.B is a monovalent organic group, E.sup.2 is a monovalent reactive group which is reactive with E.sup.1, E is a bivalent connecting group formed by the reaction of E.sup.1 with E.sup.2, R.sup.AF is a bivalent organic group formed by the fluorination of R.sup.A, etc., R.sup.BF is the same group as R.sup.B, etc., E.sup.F is a bivalent connecting group formed by the fluorination of E, etc., E.sup.F1 is a monovalent group formed by the decomposition of E.sup.F, and X is a halogen atom.