PURPOSE: To reduce leakage magnetic fields from superconducting coils and prevent the reduction of critical current at oxide high temperature superconducting current leads, by encircling the superconducting coil with ferrous ceramic magnetic shield member having a higher permeability.

CONSTITUTION: The title conduction cooling superconducting magnet device consists of a cold storage type freezer 7 comprising a first and a second cooling stages A, B, a superconducting coil 5 placed on the second cooling stage B, and high temperature superconducting current leads 6 connected with the superconducting coil 5 through electrodes 20. A magnetic shield member is installed at both ends and around the perimeter, of the superconducting coil 5. The magnetic shield member consists of a cylindrical side magnetic shield member 19A, a disk-like upper magnetic shield member 19B and lower magnetic shield member 19C. This will reduce leakage magnetic fields from the superconducting coil 5, and prevent the reduction of critical current at the high temperature superconducting current leads 6 at the leads.