Provided is an exhaust device connected to an engine body. The exhaust device includes a plurality of independent exhaust pipes, each of which has a circular cross section, and which are connected to exhaust ports of cylinders of the engine body; and a mixing pipe having a circular cross section, connected to downstream ends of the independent exhaust pipes, and through which exhaust gas that has passed through the independent exhaust pipes flows in. The independent exhaust pipes are connected to an upstream end of the mixing pipe in such a manner that parts of internal spaces of the circular cross sections overlap each other in a predetermined section from the downstream ends of the independent exhaust pipes toward upstream, and a ratio of overlapping portions of the circular cross sections gradually increases from upstream toward downstream.