A motorcycle exhaust system includes a catalytic converter (43) disposed within an exhaust passage (37) for discharging exhaust gas (G) from a multi-cylinder combustion engine (E) and operable to purify the exhaust gas (G). An upstream end of the catalytic converter (43) has different regions (S1 and S2) communicated with upstream exhaust passage portions (37a and 37a), respectively, and a downstream end of the catalytic converter (43) is communicated with downstream exhaust passage portions (37b and 37b) in a number equal to or smaller than the number of the upstream exhaust passage portions (37a and 37a). Also, the catalytic converter (43) has a partition wall (43c) extending in a direction of flow of the exhaust gas (G) for allowing the exhaust gas (G) from the upstream exhaust passage portions (37a and 37a) to flow through the catalytic converter (43) without being mixed together.