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 XSO2RA-E1 (1) with RB-E2 (2) to form XSO2RA-E-RB (3), then reacting (3) with fluorine in a liquid phase to form FSO2RAF-EF-RBF (4), and further, decomposing the compound to obtain FSO2RAF-EF1 (5), wherein RA is a bivalent organic group, E1 is a monovalent reactive group, RB is a monovalent organic group, E2 is a monovalent reactive group which is reactive with E1, E is a bivalent connecting group formed by the reaction of E1 with E2, RAF is a bivalent organic group formed by the fluorination of RA, etc., RBF is the same group as RB, etc., EF is a bivalent connecting group formed by the fluorination of E, etc., EF1 is a monovalent group formed by the decomposition of EF, and X is a halogen atom.