PURPOSE: To obtain a superconducting thin film of oxide having excellent mass productivity free from limitation of use caused by shape and critical current density in forming a superconducting thin film of oxide having a specific composition on a single crystal silicon wafer by laying a CaOxFy-based compound as an intermediate layer between the superconducting thin film of oxide and the single crystal silicon wafer substrate.

CONSTITUTION: A film of a compound shown by the formula CaOxFy (x≤0.2, 1.6≤y≤2) is formed in 400-500nm thickness by reaction metallizing method on a single crystal silicon wafer substrate. A superconducting thin film of Bi-M- Cu-O-based or Bi-Pb-M-Cu-O-based oxide is formed on the film by molecular beam epitaxial method (in the formula, M is alkaline earth metal). Enlargement in diameter, high critical current density and restriction of barrier of grain boundary can be controlled and a superconducting thin film of oxide having excellent mass productivity can be produced at low cost.