A device for removing pollutants from exhaust gases of a combustion engine, includes a longitudinal outer casing (23) defining a passage through which the exhaust gases flow, and first and second pollution-removal members (18, 20) mounted in series in the passage. The device includes a holding sleeve (38) holding the first pollution-removal member (18) in place and interposed between the first pollution-removal member (18) and the outer casing (23) and running longitudinally at least over most of the length of the first pollution-removal member (18), the holding sleeve (38) being guided in the external casing (23) and forming, between the first and second pollution-removal members (18, 20) a longitudinal thrust surface (40) against which the first pollution-removal member (18) bears.