A centrifugal fan including an impeller housing and an impeller. The impeller housing has an accommodation space, an air inlet and an air outlet. The air inlet and the air outlet are connected to the accommodation space. The impeller is located in the accommodation space. The impeller includes a hub, a plurality of blades, and at least one heat conductive annular portion. The hub is rotatably disposed in the impeller housing. The plurality of blades are connected to an outer circumferential surface of the hub. The at least one heat conductive annular portion is connected to the plurality of blades.