A method of manufacturing an antenna including: forming an integrated assembly that is configured with a core, a bobbin disposed around the core and having a flange, and a coil disposed around the bobbin; supplying a liquid filler material into an inner space of a case, the case having an opening; inserting the integrated assembly into the inner space of the case via the opening before or after the supplying of the liquid filler material; closing the opening with the flange; concentrating the liquid filler material toward the flange in the inner space; curing the liquid filler material after the concentrating so as to form a cured filler material; and fixedly supporting the integrated assembly within the case via the cured filler material at a position directly adjacent to the opening of the case.