Abstract: It is aimed to provide a wiring harness, in which a part where a wire conductor is exposed from an insulation coating is covered by a waterproof portion and which can maintain the adhesiveness of the waterproof portion to the insulation coating containing a plasticizer even if being placed in a high-temperature and high-humidity environment. A wiring harness is provided with a wire including a conductor, an insulation coating covering an outer periphery of the conductor and a conductor exposed portion, in which the conductor is exposed from the insulation coating, and a waterproof portion for integrally covering surfaces of the conductor exposed portion and the insulation coating. The insulation coating contains a plasticizer. The waterproof portion is constituted as a cured body of a resin composition containing a urethane (meth)acrylate oligomer and a nitrogen-containing monomer, which is a radical polymerizable monomer containing a nitrogen atom.