An engine generator including a soundproofing case that houses an engine and a generator therein. The engine includes an engine-side cooling fan and an engine-side inlet. The generator includes a generator-side cooling fan and a generator-side inlet. The engine generator further includes an engine-side partition and a generator-side partition fixedly disposed within the soundproofing case to define a chamber to be cooled that houses sections of the engine and the generator that are to be cooled, an engine-side air intake chamber that the engine-side inlet faces, and a generator-side air intake chamber that the generator-side inlet faces. The soundproofing case includes a cover part whose inside face is in intimate contact with the outer peripheries of the engine-side and generator-side partitions and has an exhaust vent in a part corresponding to the chamber to be cooled.