Rfid-tag reading/writing method and reading/writing device

[Problem] To provide an RFID-tag reading/writing method and reading/writing device that make it possible to increase the processing efficiency of wireless data communication and reduce the error rate of a reading/writing process as RFID tags (11) are conveyed. [Solution] This invention focuses on performing wireless data communication with RFID tags (11) via a plurality of device antennas provided along a conveyance path (18) for said RFID tags (11). Read/write-process durations are calculated from the speed at which the RFID tags (11) are conveyed along the conveyance path (18) and the lengths of the device antennas, which face RFID antennas (15), in the direction of the conveyance path (18). As the RFID tags (11) are conveyed along the conveyance path (18), wireless data communication is performed sequentially, within the aforementioned read/write-process durations, between the RFID tags (11) and the device antennas, said device antennas consisting of first device antennas (19), second device antennas (21), and a third device antenna (23), provided on the conveyance path (18) in that order from the upstream side to the downstream side.