Abstract: A muffler in an exhaust device of an engine includes a casing, a first expansion chamber, a second expansion chamber, and a third expansion chamber separately formed in the casing, and a first communication pipe, a second communication pipe, and a third communication pipe provided in the casing. The rear exhaust pipe is connected to the first expansion chamber, the first expansion chamber communicates with the third expansion chamber via the first communication pipe, the first expansion chamber communicates with the second expansion chamber via the second communication pipe, and the second expansion chamber communicates with an outside of the casing via the third communication pipe. The third expansion chamber does not communicate with an outside of the third expansion chamber except that the third expansion chamber communicates with the first expansion chamber via the first communication pipe.