To improve the cooling performance, and make a working matching set compact in a sound-insulated type engine driven working machine set, by devising cooling air intake ports and exhaust air paths.

A working machine 5 with the power generating function, which is provided with a rectifier 35 as the first working machine, is arranged in series with an engine 3, and the second working machine 6 is arranged in parallel with the engine 3. Further, an exhaust air duct 21 in which exhaust air of the engine 3 and exhaust air of the working machine 5 are joined together to be circulated, is provided, and the exhaust air duct 21 is connected to outside the sound insulating case 1. At the bottom of the sound insulating case in the neighborhood of the rectifier, a cooling air intake port for the working machine with the power generating function, is formed. Further, an air compressor 6 as the second working machine is arranged, and a cooling air intake port for the engine is formed at the bottom of the sound insulating case. A cooling air intake port for the air compressor is formed at the bottom of the sound insulating case, directly below an air tank.