Exhaust emission control device

An exhaust system including an exhaust emission control device with a post treatment unit (e.g., a selective reduction catalyst) for depuration of exhaust gas flowing therethrough is disclosed. The exhaust system includes a layout that introduces the exhaust gas into the post-treatment unit through a turnabout. An introductory part encircles an inlet end of the post-treatment unit and receives the exhaust gas through an exhaust inlet port from a direction substantially perpendicular to an axis of the selective reduction catalyst. The introduction part is formed with a first depression cambered away from the inlet end of the selective reduction catalyst and approaching toward the inlet end of the selective reduction catalyst as the first depression extends away from the exhaust inlet port and toward an introduction direction of the exhaust gas, thereby promoting uniformity of the exhaust gas flow entering the post-treatment unit.