To operate an engine driven air conditioning apparatus wherein corrosion of an outer casing panel due to scattering of drain water from an exhaust port is reduced, and the exhaust port or an exhaust hole of an exhaust top are avoided from being clogged with formed ice.

The title engine driven air conditioning apparatus is adapted such that there are provided in a machine chamber an engine 1 for driving a compressor and an exhaust muffler 4 for forcing exhaust gas of the engine 1 to flow in through a first exhaust pipe 3, and further there is provided a second exhaust pipe 5 disposed in a heat exchange chamber 15 adjacent to the machine chamber 12 for exhausting the exhaust gas of the exhaust muffler 4 to the outside. In the apparatus, the second exhaust pipe 5 is covered with a heat insulating member.