An article of a design of the present application is an exhaust gas purifying device mounted on a diesel engine and the like. As shown in a reference perspective view and various reference views of an exhaust gas purifying device mounted on a diesel engine, the exhaust gas purifying device includes an oxidation catalyst portion and a filter portion which collects particulate materials in exhaust gas. A diesel oxidation catalyst (not shown) is accommodated in the oxidation catalyst portion, and a suite filter (not shown) is accommodated in the filter portion. The exhaust gas purifying device is provided with an exhaust gas inlet and an exhaust gas outlet. The exhaust gas inlet is in communication with an exhaust manifold of the diesel engine and an exhaust pipe extending from the exhaust manifold. The exhaust gas purifying device is mounted on the exhaust manifold of the diesel engine or the like through a bracket. The oxidation catalyst portion and the filter portion are connected to each other through a flange in the exhaust gas purifying device. The internal design features of the gas purifying device and the engine to which the device is mounted are not claimed.