A centrifugal fan includes: an impeller; an upper casing that is disposed above the impeller; a lower casing that is disposed below the impeller; an outlet port that is provided between the upper casing and the lower casing and from which an air suctioned by rotation of the impeller is discharged, wherein the upper casing is provided with a flange that protrudes in an outer radial direction of the impeller from an outer circumferential edge of the upper casing, and wherein the flange partially covers the outlet port when viewed from a direction perpendicular to a rotation axis of the impeller.