To provide the fan structure of engine generator in a series matching the output of generators while reducing the cost by adding the thickness of a stator core to the outside diameter of the stator of a generator as the generator cooling fan structure as an engine generator.

In an engine generator 1 integrally comprising a generator G being driven through an engine E, a fin plate 17 is stopped, by means of fixing bolts 22, to the generator side end face of a tubular flywheel 3 secured to the output shaft 2 of the engine E while being coupled with the shaft 6 of the rotor 7 of the generator G. The fin plate 17 is made of a plate material and has fan blade parts 17a formed by bending the opposite ends to have a phase angle of about 90°, and a central blade coupling part 17b.