An exhaust system for a motorcycle provided with a multicylinder engine, includes an exhaust aggregating member for unifying a pair of exhaust passages, through which an exhaust gas exhausted from the engine is transported to a muffler, so as to form a single exhaust passage therein. The single exhaust passage is connected to the muffler without being merged with another exhaust passage. The exhaust system also includes an exhaust control valve incorporated into the exhaust aggregating member and capable of changing sectional area of the single exhaust passage formed in the exhaust aggregating member.