An optical reading device that is connectable to a control device, comprising: an optical reading unit (110, 111, 112) for optically scanning a document; a storage unit (160, 41) for storing scanned image data captured by the optical reading unit (110, 111, 112) by scanning the document; a transmission unit (40, 43) for transmitting scanned image data stored in the storage unit to the control device; and a control unit for setting at least one target area on the document so that scanned image data is captured by the optical reading unit (110, 111, 112) and stored in the storage unit (160, 41) for each of the at least one target areas, the control unit being further configured to cause the transmission unit (40, 43) to transmit the scanned image data for each of the at least one target areas to the control device, characterized in that the control unit is further configured to determine, when a plurality of target areas are set by the control unit, a transmission sequence for the plurality of target areas based on the storage size of the scanned image data of each target area, according to an ordering from large-sized to small-sized, when it is determined that control device can receive a large amount of scanned image data, so that scanned image data of target areas having large-sized scanned image data is transmitted first, or according to an ordering from small-sized to large-sized, when it is determined that control device cannot receive a large amount of scanned image data, so that scanned image data of target areas having small-sized scanned image data is transmitted first, wherein the transmission unit (40, 43) is caused to transmit the scanned image data of each of the plurality of target areas according to the order of target areas specified by the determined transmission sequence. an optical reading unit (110, 111, 112) for optically scanning a document; a storage unit (160, 41) for storing scanned image data captured by the optical reading unit (110, 111, 112) by scanning the document; a transmission unit (40, 43) for transmitting scanned image data stored in the storage unit to the control device; and a control unit for setting at least one target area on the document so that scanned image data is captured by the optical reading unit (110, 111, 112) and stored in the storage unit (160, 41) for each of the at least one target areas, the control unit being further configured to cause the transmission unit (40, 43) to transmit the scanned image data for each of the at least one target areas to the control device, characterized in that the control unit is further configured to determine, when a plurality of target areas are set by the control unit, a transmission sequence for the plurality of target areas based on the storage size of the scanned image data of each target area, according to an ordering from large-sized to small-sized, when it is determined that control device can receive a large amount of scanned image data, so that scanned image data of target areas having large-sized scanned image data is transmitted first, or according to an ordering from small-sized to large-sized, when it is determined that control device cannot receive a large amount of scanned image data, so that scanned image data of target areas having small-sized scanned image data is transmitted first, wherein the transmission unit (40, 43) is caused to transmit the scanned image data of each of the plurality of target areas according to the order of target areas specified by the determined transmission sequence.