Provided are a method of fabricating a nanostructure array and a device including the nanostructure array. Nanoscale patterning is caused at an interface of a resist layer by light passed through a focusing layer. By such nanoscale patterning, a nanostructure array is fabricated on a substrate in various ways. As the focusing layer, an array of beads or lenses is used, and a pattern of the resist layer may include a nanoscale pore-opening and an undercut structure connected to a lower portion of the opening. The method facilitates adjustment of the size and shape of nanostructures and the interval between the nanostructures. Also, performance of the device including the nanostructure array can be improved. In particular, the method and device result in a sensor having improved sensitivity and reliability optimized for an environment and purpose to be used.