A method of manufacturing an antenna comprising: forming an integrated assembly that is configured with: a core; a bobbin disposed around the core, the bobbin 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; wherein the case has a closed end that is located opposite to the opening, in the supplying, locating the closed end lower than the opening with respect to horizontal, and supplying the liquid filler material into the inner space of the case before inserting the integrated assembly into the inner space of the case, in the inserting, locating the opening higher than the closed end with respect to the horizontal, and inserting the integrated assembly into the inner space of the case containing the liquid filler material via the opening, and after the opening is closed by the flange, rotating the case until the opening is located lower than the closed end with respect to the horizontal, wherein the liquid filler material is supplied into the case in an amount that is equal to or less than a half of an inner volume of the inner space of the case. forming an integrated assembly that is configured with: a core; a bobbin disposed around the core, the bobbin having a flange; and a coil disposed around the bobbin; a core; a bobbin disposed around the core, the bobbin 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; wherein the case has a closed end that is located opposite to the opening, in the supplying, locating the closed end lower than the opening with respect to horizontal, and supplying the liquid filler material into the inner space of the case before inserting the integrated assembly into the inner space of the case, in the inserting, locating the opening higher than the closed end with respect to the horizontal, and inserting the integrated assembly into the inner space of the case containing the liquid filler material via the opening, and after the opening is closed by the flange, rotating the case until the opening is located lower than the closed end with respect to the horizontal, wherein the liquid filler material is supplied into the case in an amount that is equal to or less than a half of an inner volume of the inner space of the case.