A technical object of the invention is to improve a general purpose property of an exhaust gas purifying device for mounting, by increasing the attaching pattern of an exhaust gas purifying device, in the case that the exhaust gas purifying device is attached to a diesel engine. An exhaust gas purifying device 1 according the present invention is provided with gas purifying filters 2, 3 purifying an exhaust gas discharged from a diesel engine 70, inner cases 4, 20 internally provided with the gas purifying filters 2, 3, and outer cases 5, 21 internally provided with the inner cases 4, 20. An exhaust gas inlet pipe 16 having an exhaust gas inlet side 16a is provided in the midstream portion in a longitudinal direction of the outer case 5. An exhaust gas inflow port 12 is provided in one end side in a longitudinal direction of the catalyst outer case. An exhaust gas outlet side 16b of the exhaust gas inlet pipe 16 is structured such as to be connected to the exhaust gas inflow port 12 of the catalyst outer case 5.