A wiring harness manufacturing method and a wiring harness manufacturing apparatus is provided, wherein manufacturing costs of a wiring harness is reduced. The wiring harness manufacturing apparatus (1) has a pair of wire stocking units (10a, 10b), a pair of cutting units (11a, 11b), a pair of joining units (12a, 12b), and a case insertion unit (13). Painting devices (14,15,16) are attached to one wire stocking unit (10a). Painting devices (17,18,19) are attached to one cutting unit (11a). Painting devices (18,19) are attached to one joining unit (12a). The painting devices (14,15,16,17,18,19) color the electric wire.