PURPOSE: To make it possible to design to match any environmental condition and to reduce heat loss by constructing an oxide superconductor phase of a part to be installed on the high-temperature side and a different superconductor phase for an oxide superconductor phase of a part to be installed on the low- temperature side.

CONSTITUTION: Wire materials in two kinds of lengths are prepared for a Bi type superconducting wire 3 and a Tl type superconducting wire 4, respectively. After a combination thereof is pressed, it is made into one unit by diffusion joining to make an oxide superconducting current lead. And the number of layers of wire materials to be overlaid and the lengths of the Bi type superconducting wire 3 and the Tl type superconducting wire 4 are changed to form two oxide superconductive phases 1 having different compositions and crystal structures in a sheath material 2. A conductor to be positioned on the high-temperature side is the Tl type superconductor and a conductor to be positioned on the low-temperature side is the Bi type superconductor.