The invention concerns a leak limiter (20) for an electrolytic cell (1) for aluminium production provided with confinement means including passage openings for inserting anode rods (3). The invention is characterized in that it comprises at least one support (21), for enclosing all or part of the anode rod, and at least one flexible sealing body (30, 30a, 30b, 30c) arranged on all or part of the periphery (23) of the support (21) and designed to seal all or part of the free space between the inner edge of an opening and an anode rod (3). The invention enables enhancement of sealing conditions of casing devices of electrolytic cells.