PURPOSE: To provide an optical transmission system for radio signal which transmits signals to be transferred through a radio channel by using an optical fiber cable.

CONSTITUTION: A transmission terminal station A' is provided with a first electric/optic converting means 2' for modulating light intensity with a carrier signal Sa from a carrier signal output means 4 and outputting light to an optical transmission line (e), second electric/optic converting means 1' for modulating light intensity with an intermediate frequency signal f1 from an output means 3 for an intermediate frequency signal Sb including an information signal, and photocoupling means 10 for coupling optical signals La and Lb from optical transmission lines (d) and (e) and outputting the signal to an optical transmission line (c) for radio signal, and a transmitter B' is provided with a filtering means 8 for filtering one radio frequency component among the signals Sa and Sb outputted from an photoelectric converting means 11, which converts a light intensity modulated signal Lc transmitted through the optical transmission line (c) to an electric signal Sc, and waves mixing the frequencies of these signals and transmitting means 9' for transmitting a filtered radio frequency signal Sd.