Exhaust apparatus of internal combustion engine

An exhaust apparatus of an internal combustion engine, comprising:na sound deadening device having an expansion chamber in which an exhaust gas discharged from the internal combustion engine is introduced to extend the exhaust gas flow and to mute exhaust gas sounds, and a resonance chamber adjacent to the expansion chamber to mute the exhaust gas sounds of a specific frequency;an exhaust pipe having an upstream portion and a downstream portion positioned at an upstream side and a downstream side, respectively, in an exhaust flow direction of the exhaust gas, the upstream portion having an upstream open end connected with the expansion chamber of the sound deadening device, and the downstream portion having a downstream open end through which the exhaust gas discharged from the sound deadening device is discharged to an atmosphere; anda hollow member disposed in the exhaust pipe and having a downstream end forming an open end, and an upstream end forming an open end protruded outwardly from an inside of the exhaust pipe through the upstream open end of the exhaust pipe to be communicated with the resonance chamber and being located in a closed space surrounded by a wall portion of the sound deadening device defining the resonance chamber; andan axial length of the exhaust pipe and an axial length of the hollow member being set to match a specific frequency of the resonance chamber to a frequency of an air column resonance generated in the exhaust pipe.