A distributed multi-drop base station/repeating unit using an extension of analog optical transmission in a mobile communication system. The base station unit comprises a main unit for performing functions of a mobile communication base station, and a plurality of remote units cascaded to the main unit on a sector basis. Each of the remote units is adapted to, in a forward mode, receive an analog optical signal, perform a photoelectric conversion operation for the received analog optical signal, split the resulting electrical RF signal into electrical RF signals of two paths, amplify the electrical RF signal of one of the two paths, perform an electrophotic conversion operation for the amplified electrical RF signal, transmit the resulting optical signal, amplify the electrical RF signal of the other path and transmit the amplified electrical RF signal to an associated terminal, and to, in a backward mode, receive an analog optical signal, perform the photoelectric conversion operation for the received analog optical signal, amplify the resulting electrical RF signal, couple the amplified electrical RF signal with its own electrical RF signal, perform the electrophotic conversion operation for the coupled result and transmit the resulting optical signal.