A branch joint is provided at the rear portion of an exhaust pipe. Second exhaust pipes with a small diameter arranged one above the other are branched at a position forward of an intersecting position P with a pivot plate. The second exhaust pipes are made to intersect the inside of the pivot plate. The gap between the pivot plate and the engine can be narrowed while ensuring a smooth exhaust. The exhaust path lengths of the second exhaust pipes are made to be offset from each other so as not to be the integral multiple of the wavelength of the exhaust sound in the operating area. This allows exhaust gases to interfere with each other in the muffler. Thus, the exhaust sound can be reduced and the muffler can be downsized. This allows for the sliming of the vehicle body without lowering the output of the engine.