Method of identifying an optical cable

There is provided a method of identifying a particular optical cable out of a plurality of similar optical cables in a simple, quick and accurate manner without requiring any significant additional cost. For identifying a particular optical cable C2 out of a plurality of optical cables C1 through C3 by means of a means for transmitting optical signals 11, a signal receiving/detecting means 13 and a signal applying device 16 and by utilizing the fluctuation in the level of optical signal due to the photoelastic effect that appears when external signals are applied to a cable carrying an optical signal, external signals are applied to the outer, peripheral surface of each of the optical cable at a plurality of spots to boost the level of fluctuation of optical signal so that the particular optical cable can be identified without fail. Thus, the method of the present invention can be used to identify a particular optical cable out of a plurality of similar optical cables in an accurate and reliable manner by using a simple means of applying external signals.