Centrifugal fan

A centrifugal fan comprising:

• a main plate rotating about an axis of rotation;
• a shroud having an inlet port for introduction of air;
• and
• a plurality of blades arranged between the main plate and the shroud, each blade having a pressure surface which is directed outward of the centrifugal fan, the pressure surface including a convex portion formed near the shroud and a concave portion formed near the main plate, wherein
• the shroud has an inside surface formed as a curved surface, which is convex toward the main plate, for guiding the flow of air, the curved surface being a diffusion section extending radially so as to gradually curve away from the main plate to an outer periphery of the shroud, and
• the main plate has a curved surface extending radially so as to gradually curve away from the shroud to an outer periphery of the main plate, the curved surface of the shroud in the diffusion section at least partially overlapping with the curved surface formed in the main plate when viewed in a direction of the axis of rotation.