A reader/writer transmitting and receiving data, through wireless communications, to and from a passive type wireless tag having a nonvolatile storage unit, includes a tag selection unit selecting a target wireless tag performing the wireless communications with the reader/writer, a data transmitting/receiving unit executing data transmission/reception between the selected target wireless tag and the reader/writer, and a time information writing unit writing, when completing the data transmission/reception by the data transmitting/receiving unit, the time information on completion time of the data transmission/reception to the nonvolatile storage unit, wherein the tag selection unit selects the target wireless tag from within one or the plurality of wireless tags on the basis of the time information already written by the time information writing unit through the previous data communications with the reader/writer.