Abstract: In a sound-proof type engine working machine with a waste heat recovery apparatus, including a sound-proof type engine working machine which comprises a liquid cooled internal combustion engine and a working machine such as an electricity generator, a compressor and the like adapted to be driven by the engine and a waste heat recovery apparatus adapted to recover the waste heat from the engine, the engine cooling liquid within the water jacket of the engine is adapted to circulate through a waste heat recovery heat exchanger and a radiator, as well as the heat to be radiated in the radiator is adapted to be controlled by means of a radiated heat control device, and the engine and the working machine are horizontally arranged side by side each other within the sound-proof casing in a longitudinal direction thereof, an upper support frame is fixed on the upper side of the sound-proof casing, and the radiator and a radiator fan associated therewith are disposed on the upper support frame.