According to one embodiment, a reading device is configured to read information from an RFID tag attached to a product. The reading device includes a housing, an antenna, an opening-and-closing lid, a detector, a reading unit, and an alert unit. The housing includes an opening portion, and therein a space for accommodating the product. The antenna is provided within the space. The opening-and-closing lid is opening and closing the opening portion. The detector is configured to detect an open or closed state of the opening-and-closing lid. The reading unit is configured to read the information from the RFID tag. The alert unit is configured to issue an alert on an operation method in accordance with the open or closed state of the opening-and-closing lid and an operation state of the reading unit.