The phenomenon of resonance in a catalyst converter due to a flow of an exhaust gas is reduced without causing problems with vehicle layout, problems with manufacturing (higher manufacturing cost), or adverse influences on other facets of performance. An internal combustion engine includes an internal combustion engine main body having a fuel chamber formed in an interior, and a catalyst converter arranged in an exhaust flow channel of the internal combustion engine main body and provided with a catalyst for purifying the exhaust gas. The exhaust flow channel, which is upstream of the catalyst of the catalyst converter, is provided with a protuberance for disturbing the flow of the exhaust gas in the exhaust flow channel to reduce pressure pulsations of the exhaust gas.