A wireless IC device includes an electromagnetic coupling module, which includes a feeder circuit board having a wireless IC chip arranged to process transmission and reception signals mounted thereon, and a radiation plate. Linear loop electrodes provided in the radiation plate are electromagnetically coupled to planar electrodes located on a surface of the feeder circuit board. A signal received by the radiation plate drives the wireless IC chip. A response signal from the wireless IC chip is transmitted to the outside from the radiation plate. A frequency of the transmission and reception signals is substantially determined by inductance of the loop electrodes, capacitance between the loop electrodes and the planar electrodes, and stray capacitance generated between lines of the loop electrodes.