A stretchable conductor forming paste containing a conductive filler, a polyurethane elastomer having a glass transition temperature (Tg) of −60° C. to −10° C. and a urethane group concentration of 3000 to 4500 m equivalent/kg, and an organic solvent. Preferably, a total amount of components excluding the solvent is 100 parts by mass, a total of the conductive filler is 70 to 95 parts by mass, and an amount of the polyurethane elastomer is 5 to 30 parts by mass. The obtained paste is printed or coated and then dried to obtain a stretchable conductor, capable of forming a wiring line having good repeated stretchability.