PURPOSE: To obtain a superconducting coil having an insulation material of higher bonding strength by previously providing an outer ring consisting of a material of a line expansion coefficient which is smaller than that of the coil to the external circumference of a pan-cake coil and by hardening then under the heat treatment.

CONSTITUTION: A ring 11 is provided in the external circumference side of a wound coil 3 and the coil is tightened and fixed through a spacer 13 with a press bolt 12 using a Screw hole provided at the ring 11. In this case, a line expansion coefficient of the ring 11 is set smaller than that of the coil 3. The resin in the insulation material is hardened through the heat treatment under the condition that a compressing force is applied to the insulation materials provided between conductors. Thereby, a superconducting coil having higher bonding agent and rigidity can be manufactured.