To provide a muffler and a communicating pipe for the muffler for sufficiently absorbing an exhaust sound.

An exhaust gas introduced into a silencing chamber 2A is expanded by providing an exhaust gas introducing port 4A having three or more plural silencing chambers 2A-2C, and directly flowing the exhaust gas of an internal combustion engine into the utmost upstream silencing chamber 2A out of these chambers 2A-2C. Communication pipes 6 and 7, for communicating the adjoining chambers of the chambers 2A-2C, are provided to provide partitioning walls 9 on both the ends of these pipes 6 and 7, and many communicating holes 8A (8A1-8A4) are provided on given positions on the outer periphery in accordance with the chambers to be communicated. In feeding the gas into the adjoining chambers 2A-2C, the gas repeats contraction and expansion by the holes 8A of the pipes 6 and 7 to loss pressure, and silence a sound.