PURPOSE: To enable mechanical strength of an insulation substrate to be high, smoothing properties to be superb, high density wiring of a superconductor to be realized, and to obtain a superconductive characteristics with improved reliability by wiring an oxidation superconductor on a substrate including MgO and Al2O3.

CONSTITUTION: A desirable range of a substrate material is 95∼99weight% MgO, 1∼5weight% Al2O3, and the total weight% MgO and 99.5weight% or more Al2O3. As a superconductor to be wired, any superconductor which does not deteriorate due to reaction with substrate and an oxidation superconductor with a large adhesion strength can be used. Ba-Y-Cu-O superconductor is desirable since it has a better conformity with an insulated substrate and has a higher critical temperature. After mixing materials to obtain a desired composition, a forming assistant is added as needed, and a desired shape is formed, an insulation substrate can be obtained by sintering. For example, screen printing method is used to perform wiring on this insulation substrate using an oxidation superconductor.