A method for fabricating a nanoantenna array may include forming a resist layer on a substrate, forming a focusing layer having a dielectric microstructure array on the resist layer, diffusing light one-dimensionally in a specific direction by using a linear diffuser, forming an anisotropic pattern on the resist layer by illuminating the light diffused by the linear diffuser on the focusing layer and the resist layer, depositing a material suitable for a plasmonic resonance onto the substrate and the resist layer on which the pattern is formed, and forming a nanoantenna array on the substrate by removing the resist layer and the material deposited on the resist layer. A light diffusing angle by the linear diffuser and a size of the dielectric microstructure are determined based on an aspect ratio of the pattern to be formed.