To improve tag read/write accuracy.

A tag access device 1 is provided for accessing RFID tags 11 having first antennas with radio wave directivity in a longitudinal direction of a plurality of test tubes 10, which are arranged at predetermined intervals. The tag access device 1 is disposed in a direction right opposite to the radio wave directivity. At an access to the RFID tag 11, the tag access device 1 includes multi-filar helical antennas 22 that maintain electric field intensity at the center portion to be accessible to the RFID tag 11.