The invention provides an electrical cable reuse method which reduces a long time stock of cables. For assembling a wiring harness, step S1 reuses special electrical cables stocked in an electrical cable storehouse, and the cables having been colored in a first color are coated with a second color. Step 2 cuts ordinary cables and special cables each in a desired length, removes a part of a cable sheath of each cable, and fits a terminal piece to the exposed part. Step 3 connects ordinary cables and the special cables with each other. Step 4 inserts the terminal piece into a connector housing.