Provided is a broadband circularly polarized antenna using a metasurface. The antenna includes a lower substrate, an upper substrate stacked on the lower substrate, a radiator, which is located between the lower substrate and the upper substrate, has a rectangular patch shape in which two triangular removed parts are formed by removing opposite corners in a triangular shape, extends so as to have a predetermined width and length from one end of a hypotenuse of one triangular removed part of the triangular removed parts, and includes an extended strip having a feed hole formed therein, and the metasurface formed on an upper surface of the upper substrate and including a plurality of unit cells. The antenna has improved performance, such as a low profile, a broadband circular polarization characteristic, a high gain characteristic, and the like.