To provide a transmission line which can be formed, without increasing the number of manufacturing processes, is small in signal deterioration caused by crosstalk and is capable of high-density wiring, and has proper radiofrequency transmission characteristics.

There are provided pairs of wiring conductors composed of signal conductors (2a, 3a, 4a) and pairing wiring conductors (2b, 3b, 4b), which either form closed-loop circuits with the signal conductors, or become pathways for return current, and are larger than the signal conductors in conductor width, opposed to each other with a dielectric (1) in between. The two or more pairs of wiring conductors are arranged side by side so that a plurality of signal conductors, or pairing wiring conductors do not adjoin each other.