To facilitate various work, such as extracting exhaust gas in a exhaust pipe.

This device is provided with a water jacket in an exhaust pipe 16 with a catalyst disposed in the upstream of an exhaust gas passage, and a temperature sensor for detecting the temperature of an exhaust system. An exhaust gas extraction opening 26 is formed at the exhaust pipe 16, and an exhaust gas extraction pipe for extracting the exhaust gas in the exhaust pipe 16 and plug 40 are selectively-fitted to the exhaust gas extraction opening 26 so as to be detachable. A cover 45 is fitted at the outer surface of the exhaust pipe 16 so as to cover the exhaust gas extraction opening, and at least a part for covering the exhaust gas extraction opening 26 in the cover 45 is formed so as to be capable of being opened and closed. A cooling water delivery opening for delivering the cooling water of an engine 8 directly into the exhaust gas passage of the exhaust pipe 16 is formed at the exhaust pipe 16, and the exhaust gas extraction opening is formed in the upstream of the cooling water discharge opening.