A remote device of an optical relay system includes first and second remote driving units each extracting transmission signals of different frequency bands from downlink Radio Frequency (RF) signals provided from an optical conversion unit and outputting the transmission signals; and a downlink path control unit receiving the downlink RF signals from the optical conversion unit and transmitting the downlink RF signals to the second remote driving unit through the first remote driving unit, or transmitting the downlink RF signals to the second remote driving unit by bypassing the first remote driving unit.