Provided is an order-receiving production system and so on of a wire and wiring harness, by which the cost of the wire and a product using the wire can be prevented from increasing and the resource-saving can be attained. An order-receiving production system 1 of a wiring harness includes a wire-producing department 14, a wiring harness-assembling department 15 and a production control department 16. The production control department 16 forwards a first ordered quantity data D1, second ordered quantity data D2 and third ordered quantity data D3, each data meeting the received ordered data D, to a resin-producing department 44, core wire-producing department 45 and additive-producing department 46, respectively. The departments 44, 45 and 46 produce a pellet, core wire and additive with the respective necessary amount, respectively, and send them to the wire-producing department 14. The wire-producing department 14 extrudes a mixture of the pellets and additive onto a circumference of the core wire while simultaneously mixing the pellets and additive so that the core wire is coated with the mixture, and sends the wire produced to the wiring harness-assembling department 15 for assembling a wiring harness.