An exhaust system for a motorcycle provides enhanced steering stability and improved function for purifying exhaust gas. Front exhaust pipes connected with front cylinders of a V-type engine are joined to a front part of an exhaust chamber. Rear exhaust pipes connected with rear cylinders of the engine are joined to an upper part of the exhaust chamber. Exhaust gases discharged from both the front and rear exhaust pipes are unified within the exhaust chamber, and a catalyst is disposed in the vicinity of the unifying section. The length of the rear exhaust pipes is shorter than the length of the front exhaust pipes. High-temperature exhaust gas is introduced to the catalyst contained within the exhaust chamber via the rear exhaust pipes.