To easily separate a wire material and an insulating body of an unnecessary wiring cable from each other, and to reduce the plastic waste by using a biodegradable polymer or the mixture thereof as an insulating body of a wiring cable.

In this wiring cable 10, a biodegradable polymer or the mixture thereof is used as an insulating body 13 (11: wire material) of a wiring cable. The wiring cable can be used in the environment, under which decomposition of polymer due to the micro-organism is generated, by coating the peripheral surface of the insulating body 13. This wiring cable is embedded in the culture medium, which can decompose the biodegradable polymer, so as to separate the insulating body and the wire material from each other (a protecting film 41 is peeled, or this protecting film 41 is cut, and thereafter, the wiring cable is embedded in the culture medium).