Abstract: A fuel saving device for increasing the fuel mileage of a moving vehicle is disclosed. The number of miles per gallon of fuel is increased by the present invention through a device mounted on top of a vehicle, which device includes a housing having a length substantially equal to the width of the vehicle, an air intake at the front of the housing and a motor driven rotor having blades which are further driven by the oncoming wind pressure created by the moving vehicle. The device also includes means for deflecting the air from the housing over the remaining portion of the vehicle and positioned in cooperative relationship with the rotor to not only reduce air friction but also to create a propulsion of air at the rear of the housing to drive the vehicle forward. A motor means drives the rotor independently of the forward speed of the moving vehicle.