A superconducting wire according to the present disclosure includes: a base material; a superconductor layer formed on each of the respective surfaces of the base material; and a conductive protection layer formed on each of the surfaces of the respective superconductor layers. The thickness of each of the conductive protection layers is 5% or less of the skin depth when a high-frequency current flows through the superconducting wire. The material for forming the conductive protection layer may be, for example, silver.