A reading device includes a placing table supporting an article to which an RFID tag is attached. An antenna is configured to emit a radio wave for communicating with the RFID tag toward the placing table. A reading unit is configured to read tag information including a tag identifier identifying the RFID tag by communicating with the RFID tag via the antenna while the placing table and the antenna are integrally moved. An extracting unit is configured to extract a tag identifier in which an amount of change in phase information is a predetermined value or less, based on the phase information of a response wave obtained from the RFID tag when the tag information is read. An outputting unit is configured to output the tag information including the tag identifier extracted by the extracting unit.