Provided are an RF powder particle, an RF powder, and an RF powder-containing base that can make it difficult to fabricate, for example, forged documents or forged bank notes with respect to sheet-like objects having high proprietary values, such as bank notes, and that allow necessary information to be stored in each of the large number of particles which are each provided with a tank circuit having a predetermined resonant frequency. The RF powder particle includes a coil 24 (inductance element) as a magnetic filed coupling element and a condenser 25 (capacitance element) connected to the both ends of the coil on an insulating surface of a substrate 22 and is configured so as to form a tank circuit 31 by the inductance element and the capacitance element. The tank circuit 31 functions as a circuit in a resonance state or in a non-resonance state in accordance with conditions in response to a high-frequency magnetic field from outside.