In an exhaust system for a motorcycle in which an engine main body of a multi-cylinder engine has an oil pan on a lower portion thereof, and is mounted on a vehicle body with a plurality of expansion chambers being connected to a downstream side of an assembled portion of a plurality of exhaust pipes that extend out of the respective cylinders of the engine main body, respectively. The muffler includes a first expansion chamber that is connected to the assembled portion and the other expansion chambers that are the assembled portion are disposed on one side of the oil pan. The first continuous to the first expansion chamber. The respective exhaust pipes and expansion chamber is disposed on the other side of the oil pan with the other expansion chambers being disposed to the rear of the engine main body.