The invention discloses a method and its device for acquiring swiftly and firmly the connectivity information of electric conductor cords for connecting a plurality of apparatus groups or switching boards in information wiring facilities. The unused extra cores of an electric plural core conductor cord for connecting every apparatuses of apparatus groups A and B with each other through switching boards are connected to a voltage applicator and a voltage (or current) detector through information collecting connectors and the electric connectivity restrictions between every apparatuses of the apparatus groups of the electric conductor cord described above are acquired depending on its electric conduction. According to the invention, the connectivity information of the electric conductor cords in information wiring facilities can be obtained accurately and firmly. Furthermore, the use of the extra cores enable to reduce the cost of the device and to easily apply the invention to the facilities already built.