The present invention relates to an axial flow fan and, more particularly, to an axial flow fan comprising: a hub; and a plurality of blades that are disposed radially on the circumference of the hub such that roots of the blades are coupled to the hub, wherein the blades are formed so as to have a waveform shape such that a position of a trailing edge gradually approaches and recedes from a leading edge repeatedly, the trailing edge is positioned on the same plane, and an installation angle changes in the lengthwise direction of the blades.