An RFID tag is providing for transmitting and receiving a communication signal. The RFID tag includes a base material, antenna patterns formed on the base material, and an RFIC package connected to the antenna patterns. The antenna patterns are defined by conductor patterns. The whole of the antenna patterns resonate at a communication frequency, and each of the plurality of conductor patterns has a line length that does not cause resonance at a frequency in a microwave band for electromagnetic wave heating higher than the communication frequency.