PURPOSE: To obtain a copper clad substrate excellent for the magnetic shielding effect by constituting the copper clad substrate of a superconductive board and a copper foil adhered to the superconductive board through an insulating layer.

CONSTITUTION: A copper clad substrate is constituted of a superconductive board 4 and a copper foil 3 adhered to the superconductive board 4 through an insulating layer 2. When the superconductive board 4 presents a superconductivity phenomenon, the anti-ferromagnetism is also presented at the same time. Accordingly, the magnetism can't pass through the superconductive board 4. Therefore, even a ferromagnetic substance gets close to the superconductive board 4, the magnetism from the opposite side based on the border of the superconductive board 4 has no effect on the ferromagnetic substance. According to the constitution, the copper clad substrate excellent for the magnetic shielding effect can be obtained.