To provide an IC tag which can deal with different communication frequency and can be adapted to material properties of a conductive article being an object to be stuck to, or various use environment.

An RFID tag 10 includes an IC chip 4 and a single winding loop coil 11 which are mounted on a substrate. The RFID tag 10 has means for being partly fixed to a conductive article. An input terminal of the IC chip 4 is connected to the loop coil 11. Imaginary part impedance of the IC chip 4 and imaginary part impedance of the loop coil 11 are conjugate to each other, or, the imaginary part impedance of the loop coil is larger than the imaginary part impedance of the IC chip.