A self-healing wire includes, an electric wire arranged on a substrate, and a hybrid structure in which the electric wire is covered with at least one fluid selected from the group consisting of a fluid having conductive particles dispersed therein and a fluid having metal ions dissolved therein, formed on a healing portion for a crack to be generated in the electric wire. And a stretchable device includes the self-healing wire formed on a stretchable base material and an electric element mounted only on a base material higher in rigidity than the stretchable base material. Even when a crack is generated in the electric wire due to stretching of the substrate having flexibility, the crack is bridged by the conductive particles or a solid metal deposited from the metal ions in the fluid. Thus the self-healing wire and the stretchable device having both high conductivity and high stretchability are provided.