To search for presence of an electromagnetic induction function in a carbon fiber (CF) since an antenna for receiving a radio wave is heretofore made of metal such as a copper wire having conductivity and exhibiting electromagnetic induction action and metal is also used for a ground, while if a radio wave is received by an antenna and a ground of a conductive CF that substitutes for metals of finite resources, the conductive CF exhibits good radio wave receiving performance.

In a radio wave receiving circuit of Fig.2, when a CF is connected as an antenna to an antenna connecting terminal 1-A, a CF is connected as a ground to a ground connecting terminal 2-E and a radio wave of a specific frequency is tuned by a variable condenser 4-VC, an electromotive force and a terminal current generated at load connecting terminals 7-a and 8-a become larger than those in a case where a metal antenna and a metal ground are used. From a result thereof, it can be confirmed that the CF has an electromagnetic induction function superior to that of a metal.