An axial flow fan includes a housing that is formed by a process including injection molding includes a tapered surface at a frame portion thereof. One end of at least one rib is connected to an attachment portion which is a part of a stator portion of a motor portion, and the other end the rib is connected to a base portion protruding from the tapered surface. Two inclined surfaces connected to the tapered surface at the base portion and arranged in a circumferential direction with respect to a central axis are inclined such that the further a portion of the inclined surface from the central axis is, the further the portion is from a center of the rib. As a result, an air flow disturbance generated by the base portion between the rib and the frame portion is minimized, thereby reducing a noise generated due to the air flow disturbance.