Abstract: An exhaust gas purifier for internal combustion engine, has a porous filter impregnated with a desired adsorbent or a porous filter made of bulk metal catalyst. Instead of extending perpendicular to the main axial direction of the exhaust pipe, the filter extends axially and is mounted on a metal screen cylinder having a baffle which diverts the flow of exhaust gas toward and through the cylinder and filter. In this manner, the exhaust gas flows axially into the screen cylinder and then passes radially through the filter to a second flow passage which is connected to the purifier outlet. Very low back pressure is obtained with this arrangement.