PURPOSE: To enable forming hard and brittle high-temperature superconducting ceramics into a board of arbitrary size and shielding a leakage magnetic field, by providing a hollow part inside a metallic thin film and filling the hollow part with a high- temperature superconducting material.

CONSTITUTION: A metallic thin plate 1 (superconducting magnetic shielding plate) is comprized of a metallic thin plate box 2 with rising side plates 2b provided around a base plate 2a like in one body with the base plate 2a, and a metallic thin plate cover 3 being able to cover the opening of the box 2. Inside the box 2, high- temperature superconducting ceramic powder 4 is laid all over arbitrarily in thickness, and the cover 3 is jointed by the method of soldering or diffusion bonding etc. When a metallic thin plate 1 like this is burned in a temperature range that suits for sintering high-temperature superconducting ceramic powder 4, a high-temperature superconducting ceramic magnetic shielding plate can be obtained. This enables filling the ceramic powder having extremely bad liquidity easily and uniformly, and also enables preventing the superconducting characteristics from deteriorating because of the deoxidation of the superconducting ceramics in time of sintering, by providing an oxygen supplying hole or an oxide ceramics coated layer.