A motorcycle comprises a housing box arranged on at least a side of the right and left sides of the rear portion of a body frame, a gas discharge muffler arranged on one of a right side and a left side of a rear wheel, wherein the gas discharge muffler forms a portion of a gas discharge structure of the engine carried on the frame. A muffler assembly composed of the gas discharge muffler and a muffler cover covering the muffler is configured on a side of the left and right sides of the rear wheel, a housing box arranged on the other of the right side and the left side of the rear wheel, said housing box has a pseudo muffler assembly, wherein a shape and size of said pseudo muffler is substantially similar to a shape and size of said muffler assembly, the box is arranged substantially parallel to the muffler assembly.