PURPOSE: To improve mechanical strength and cooling effect by a construction wherein an insulated spacer is placed in between superconductors, the insulated spacer being prepared by gluing a plurality of insulated pieces whose surfaces are coated with a semihardened adhesive agent to glass cloth at preselected intervals.

CONSTITUTION: Both surfaces of a small piece 4 formed of an epoxy glass or epoxy laminar sheet is coated with epoxy resin to form an insulated piece 5. The insulated pieces 5 are glued at preselected intervals to the surface of glass cloth 6 in the form of meshes and a rectangular insulating material and furthermore the epoxy resin of the insulated piece 5 is semihardened to form a semihardened resin layer 7. The insulated spacer thus formed is installed in between super conductor layers.