Substrate embedded horn antenna includes a dielectric, metal patterns, metal vias and a ground plate. The metal patterns are embedded by being stacked in dielectric. Metal patterns are hollow rectangle types or hollow circle types. Metal vias connect layers of metal patterns by being embedded between layers of metal patterns. Ground plate is formed in an upper side of dielectric. Metal patterns form waveguide structure by being stacked in radial shape. Waveguide structure propagates electromagnetic wave by focusing electromagnetic wave. Embedded horn antenna capable of selectively using vertical radiation and horizontal radiation may be implemented using the via and metal pattern in dielectric substrate. Embedded horn antenna may be implemented in small size with high gain. Vertical embedded horn antenna and horizontal embedded horn antenna may be implemented in a substrate. Method of manufacturing embedded horn antenna capable of selectively using vertical radiation and horizontal radiation may be provided.