The present invention relates to an aperture antenna capable of controlling a shape of a radiated beam without changing a structure of an aperture antenna by connecting a beam controller with a single aperture antenna. the aperture antenna including a beam controller according to the present invention includes: a waveguide; an aperture horn of which one end is connected to the waveguide and the other end is provided with an opening; and a beam controller including a feeding unit connected to the opening and provided with a plurality of slits, a dielectric layer connected to the feeding unit, and a plurality of patches connected to the dielectric layer to control a beam shape of a signal introduced into the feeding unit and radiated through the patches.