A support member (40) is provided on a cylindrical member (23) of an upstream cylinder (22). A connector portion (34C) of a first temperature detector (34) for detecting the temperature of exhaust gas flowing into an oxidation catalyst (25), a connector portion (35C) of a second temperature detector (35) for detecting the temperature of the exhaust gas flowing into a particulate matter removing filter (31), and a sensor portion (39A) of a pressure detector (39) for detecting the front and rear pressures of the particulate matter removing filter (31) are arranged to be mounted on this support member (40). Accordingly, the support member (40) is capable of supporting the connector portions (34C, 35C) of the temperature detectors (34, 35) and the sensor portion (39A) of the pressure detector (39) in one location in a concentrated manner, so that harnesses on a controller side can be easily connected thereto.