The present invention relates to an RF tag comprising a magnetic antenna for transmitting and receiving information using an electromagnetic induction method, and an IC mounted to the magnetic antenna, wherein the magnetic antenna comprises a magnetic core and a plurality of coils formed on the magnetic core; the coils each have an inductance L1 satisfying the specific relational formula, and are connected in parallel to each other in an electric circuit and disposed in series on the magnetic core; and a combined inductance L0 of the magnetic antenna satisfies the specific relational formula. The RF tag of the present invention is used as a magnetic antenna for information communication using a magnetic field component which is capable of satisfying both reduction in size and improvement in communication sensitivity.