A windmill, including a first end plate, a second end plate, and a plurality of primary blades disposed between the first end plate and the second end plate. The first end plate includes a central part provided with a base connected to a motor shaft. The second end plate includes a central part provided with an air inlet; the space between every two adjacent blades forms an air channel. The plurality of primary blades each includes an outmost end with respect to the central part of the first end plate, and the outmost end extends out of an outer edge of the second end plate. The connection line of every two adjacent outmost ends of the plurality of primary blades forms a circle, and the diameter D1 of the circle is larger than the diameter D2 of the second end plate.