A method of manufacturing a centrifugal fan is provided that includes cutting a metal sheet to form a positive pressure surface forming member and a negative pressure surface forming member, respectively, forming a positive pressure surface and a negative pressure surface; pressing the positive pressure surface forming member and the negative pressure surface forming member to form a first curved surface forming the positive pressure surface and a second curved surface forming the negative pressure surface; trimming the positive pressure surface forming member provided with the fast curved surface and the negative pressure surface forming member provided with the second curved surface to form a shroud bonding surface and a main plate bonding surface; bending the shroud bonding surface and the main plate bonding surface; bonding the positive pressure surface forming member and the negative pressure surface forming member to each other; and bonding the shroud bonding surface and a shroud to each other and bonding the main plate bonding surface and a main plate to each other in a bonded state of the positive pressure surface forming member and the negative pressure surface forming member.