a centrifugal blowing fan includes a back yoke made from metal , having a substantially bottomed cylindrical portion around a rotating shaft of a motor , an inner surface attached with a magnet of the motor mounted thereon and a flange portion disposed around a periphery of an opening of the cylindrical portion ; and a cylindrical impeller made from resin , having a plurality of blades circumferentially arranged , an annular collar portion joined with first ends of the plurality of blades and a doughnut - shaped disk portion joined with second ends of the plurality of blades , wherein the disk portion has at least one fitting , and the flange portion has at least one fitted space receiving the at least one fitting so as to concentrically and fixedly connect the impeller and the back yoke .