There is provided a resin fan capable of enhancing the mechanical strength in a weld part in view of the direction of reinforcing fiber. On the outer peripheral surface 16a of a cylindrical rib 16, convex parts 30 are formed in the middle portions between the portions in which radial ribs 18 adjoining each other are connected to the cylindrical rib 16. The cylindrical rib 16 is formed so that the thickness T in the radial direction thereof is decreased gradually from the base part 16c thereof toward the tip end part 16d. Further, the height H1 of the cylindrical rib 16 is set so as to be larger than the height H2 of the radial rib 18. Thereby, at the time of molding, the resin flows in the portions of the cylindrical rib 16 and the convex parts 30 are complicated, and thereby the orientation of glass fiber mixed in the resin is complicated.