PURPOSE: To perform efficient flow without confusing the flow of cooling air by a method wherein a flow straightening cover in the shape of a streamline in cross section is arranged in an inlet through which cooling air flowing through an electric motor is caused to flow by means of an impeller and a cylindrical wire gauge delivery cover is arranged in an outlet facing the base part of the impeller.

CONSTITUTION: An electric motor holding ring 11 is fixed to the inner part of a blower casing 1 situated upper stream from an impeller 5 through a radial mounting fitment 2. A drip-proof protection type electric motor 3 is fixed to a flange 12 with which an electric motor holding ring 11 is provided and the impeller 5 is mounted on an electric motor shaft 4. A flow straightening cover 13 is arranged on the impeller opposite side of the electric motor 3, and the inner peripheral part thereof forms a wire gauge through which an electric motor cooling air is inputted. Meanwhile, a cylindrical delivery cover 15 made of a wire gauge through which electric motor cooling air is discharged is mounted facing the base part of the impeller 5 on the impeller side of the electric motor 3 in a state to be supported to the electric motor protecting ring 11 and a cover support 14. This constitution provides a small axial flow blower the efficiency and capacity of which are increased through prevention of disturbance of air flows 6 and 7.