A method includes a step of preparing a strap having a connecting metal pattern formed on a base, and mounted with the circuit chip, the pattern connecting a circuit chip to a metal antenna pattern. A substrate has a concave section which houses the circuit chip and is formed on a first face. The metal antenna pattern extends over a first face and a second face of the base so as to circle them except for the concave section and to have the both ends positioned across the concave section. The method includes a connection step of positioning and directing the strap and the substrate to house the circuit chip in the concave section and covering the strap and the substrate with a covering material so as to fix the strap and the substrate in a state where the connection metal pattern is connected to the metal antenna pattern.