Problem: The objective of the present invention is to provide a technique to enable more accurate measurement of oxygen contained in an exhaust gas in an exhaust device provided with an oxygen sensor.Solution: A catalyst which cleans the exhaust gas is provided in an exhaust pipe in an exhaust device that includes a muffler coupled downstream of the exhaust pipe, and an oxygen sensor is mounted on a pipe portion that is disposed downstream from the catalyst and that is directly coupled to the catalyst. The oxygen sensor is provided substantially perpendicular to the axial direction of the pipe portion through which the exhaust gas flows. The oxygen sensor includes a detecting portion, the detecting portion is disposed in a recessed portion formed in the muffler, and a wire is disposed on an outer side of the recessed portion.