According to an embodiment, there is provided a label printer including a conveying mechanism, an RFID reader and writer, a communication intensity information acquisition unit, and a maximum communication intensity position determination unit, and an optimal communication position calculation unit. If communication with the plurality of RFID tags occurs simultaneously in the RFID reader and writer while conveying the mount by the conveying mechanism along the conveying route, the communication intensity information acquisition unit acquires information indicating a communication intensity between each of a plurality of the RFID tags and the RFID reader and writer in correlation with identification information of each of the RFID tags. The maximum communication intensity position determination unit determines a maximum communication intensity position, at which a communication intensity capable of being correlated with the identification information of each of the RFID tags becomes the maximum, on the basis of a tendency of a variation in the communication intensity of each of the plurality of RFID tags which accompanies the conveyance along the conveying route, and a conveying distance of the mount by the conveying mechanism. The optimal communication position calculation unit calculates an optimal communication position with the RFID tags of the plurality of labels adhered to the label paper on the basis of the maximum communication intensity position determined with respect to each of the plurality of RFID tags.