PURPOSE: To carry out many cases of discrimination of flat wires of a small number of sort and match them various colors in wiring places by putting respective various different colors on two wide surfaces of covering layers.

CONSTITUTION: Three conductors 11-13 arranged in parallel at prescribed intervals are covered with a covering layer 2 made up of insulating material such as vinyl chloride resin, etc., over the whole surface and integrally. Then, the whole of the covering layers are colored white and one surface 21 of two side surfaces 21, 22 opposed to each other toward two outside is coated with a thin layer 3 of blue vinylchloride resin, so that respectively different colors are applied to two surfaces 21, 22. It is thereby possible to make many cases of discrimination with small number of sort and match various colors of wiring places, so that the flat wire is convenient for manufacture and storage.