Blower

A blower is designed such that a backflow of air from a ventilation path into a cooling-air exhaust path is prevented by a fan-side rib and an electric motor casing-side rib. The electric motor casing-side rib is formed on an external side of the fan in a fan radial direction such that a distance between the fan-side rib and the electric motor casing-side rib in the fan radial direction becomes long. Accordingly, a flow of an electric-motor cooling air is less disturbed, and the electric-motor cooling air can be secured sufficiently. As a result, an electric motor can be cooled sufficiently, an abrasion of a brush is restricted, and a copper powder of a material making the brush is prevented from flowing into the ventilation path with the electric-motor cooling air.