Provided is a method of choosing a communication mode of an RFID device which supports near-field communication and far-field communication, including: interrupting generation of a self RF field signal; determining whether or not an RF field signal for near-field communication is detected; choosing the near-field communication mode when an external RF field signal for near-field communication is detected; and generating the self RF field signal for far-field communication when the external RF field signal for near-field communication is not detected, and choosing the communication mode according to whether or not a response signal is received.