A soundproof type engine generator has a first external air inlet and a second external air inlet formed on a soundproof case K. A first cooling passage guides external air drawn in through the first external air inlet through a duct to a first fan, then from the first fan to a generator and discharges the air out of the soundproof case K. A second cooling passage guides external air drawn in through the second external air inlet to an engine using a second fan and then discharges the air out of the soundproof case The first fan is made up of a disk-like planar part, a plurality of first blades and a plurality of second blades, respectively provided radially on both head and tail sides of the planar part. External air drawn with the plurality of first blades through the first external air inlet is guided through the duct to the generator, and discharged out of the soundproof case. Air in the soundproof case is discharged with the plurality of second blades out of the soundproof case. The soundproof type engine generator effectively cools the interior of the soundproof case and simplifies the constitution of the air feed passage via the layout and configuration of the fan.