Abstract: In a ground cable to be applied to an on-vehicle wiring harness or the like, the aim is to make it easy and simple to conduct the waterproofing work. A first sealant 6 of the UV-cure type having as a contact angle with respect to the bare conductor 1a of the ground cable 1 an acute one and a viscosity of 15-500 mPa·s is delivered by drops onto the bare conductor. The first sealant 6 is delivered by drops onto a second sealant 7. The first and second sealants 6 and 7 are irradiated by ultraviolet rays. This permits the first sealant 6 to, without the need to suck-decompress the interior of the ground cable 1, by dint of capillarity, spontaneously permeate into the cable core 1b of the ground cable 1 to be then cured. Even in case where a ground terminal 2 has a pair of ground cables 1 crimped thereonto, each ground cable 1 permits an adequate amount of the sealant 6 to, with ease, permeate it.