Abstract: The invention relates to a catalytic combustion engine exhaust gas purifier with additional air supply. The exhaust gas purifier comprises a housing structure (1) accommodating an exhaust gas inlet (2), at least one catalyst element (3), means (4) for laminarizing the exhaust gas flow, means (5 and 6) for dividing the housing structure (1) into several chambers (7-9), an exhaust gas outlet (10) and, additionally, means (11) for supplying additional air (17 and 18) into the exhaust gas flow (14 and 15) in the housing structure (1). One or more suction plates (19 and 20) are provided in the chamber (8) after the means (4) laminarizing the exhaust gas flow and at the same time in the vicinity of the means (11) supplying additional air.