Precursor of superconducting wire and method of manufacturing superconducting wire

Proposed is a novel embedded structure for suppressing a disturbance in the cross sectional shape and a non-uniform deformation of a metal member arising in a precursor when producing an MgB2 multi-core wire material by a surface reduction process. This superconductive multi-core wire material precursor is characterized by having: soft Cu and Fe pure metals disposed in the center; mixed powder elements, each comprising as a sheath material a metal such as Fe or Nb having a barrier effect preventing a reaction between Mg and Cu, the mixed powder elements being disposed in a form that surrounds the periphery of the soft metal serving as the central material; and disposed around these, an outer shell layer produced from a harder metal than the central material and the sheath material.