Engine with exhaust gas treatment apparatus

An object of the present invention is to avoid vibrational damage to an exhaust gas treatment apparatus attached by way of an exhaust pipe to an engine body (1). The casing of the exhaust gas treatment apparatus (4) consists of a plurality of casing units (5,6,7) which are separable from each other. Connection flanges (8,9,10,11) are disposed in respective end portions of the casing units (5,6,7), the casing units (5,6,7) are coupled together by a connection of the connection flanges (8,9,10,11), and the exhaust gas treatment apparatus (4) is supported by the engine body (1) through the connection flanges (8,9,10,11).