In order to provide a method of manufacturing a bow tie antenna by using a photolithography of a comparatively low level, a truncated quadrangular pyramid is formed by forming on a substrate an etching mask of a shape similar to a top face of the truncated quadrangular pyramid, and isotropy-etching the substrate with the etching mask being made a mask material. Thereafter, metal films are formed on two opposite side faces of the truncated quadrangular pyramid by injecting a vacuum deposition source from a front of each of the faces and a direction parallel to the substrate.