A muffler of a vehicle includes a first muffler body so as to form a first chamber, at least a second muffler body including a housing, one end portion opened and the other end portion closed, wherein one of the second muffler bodies is fitted into the other end portion of the first member to form a second chamber and the other second muffler bodies are fitted into each other through the one end portions in series to form third chambers if more than one second muffler bodies are assembled, an inflow pipe to connect the outside with the first, second and/or third chamber by passing the one end portion of the first muffler body, and an outflow pipe to communicate the first, second, and/or third chamber with the outside by passing through the other end portion of the last second muffler body.