Abstract: A radio frequency IC device includes a radio frequency IC chip arranged to process a transmitted/received signal, a printed circuit board on which the radio frequency IC chip is mounted, an electrode arrange on the circuit board, and a loop electrode that is arranged on the circuit board so that the loop electrode is electrically connected to the radio frequency IC chip and is coupled to the electrode by electromagnetic coupling. The electrode is coupled to the radio frequency IC chip via the loop electrode so as to transmit or receive a high-frequency signal. A power supply circuit board including a resonance circuit and/or a matching circuit may be disposed between the radio frequency IC chip and the loop electrode.