To obtain excellent cooling effect while attaining miniaturization by providing the introducing port of a cooling air passage leading sucked cooling air to the stator part and the muffler part of a generator in the vicinity of the control unit of the generator so as to introduce air after passing through the control unit into the cooling air passage.

The interior of a portable engine generator is divided into an engine arranged space and a generator arranged space with a fan casing 21, and by rotating a first cooling fan 20 integratedly provided with the crankshaft 12B of an engine 12, cooling air is sucked from slit-like cooling air sucking ports 34 provided on the bottom face of a sound-proof front cover 2, to cool the main parts of the engine 12 such as a cylinder 12A. By rotation of a second cooling fan 29 fitted to the outer circumferential face side 26a of a rotor supporting plate 26 opposite to a shroud 31, cooling air sucked from a suction port 35 cools a control circuit unit 28, a stator coil 27, a muffler, and the like, and then the air is discharged outward through a duct.