PURPOSE:To prevent a filler in a transition portion from moving when a superconducting coil is mounted on a coil mounting frame and increase the reliability of the interlayer insulation in the transition portion by arranging the transition portion of the superconducting coil densely in a linear section on one side of the coil and mounting the superconducting coil on the coil mounting frame after the interlayer insulation substance in the transition portion is semi-hardened in a state in which the coil is wound around a temporary bobbine. CONSTITUTION:A superconducting coil 3 is wound around a rectangular spool 9 beforehand. Then, it is dismounted from the spool 9, and a straight line portion 3a, an arc portion 3b, a corner portion 3c and a transition portion 10 are assembled into a slot 2 formed on the outer circumference of a coil mounting frame 1. The superconducting coil 3 is insulated to the ground with respect to the coil mounting frame 1 by a wedge insulation 5 and insulation 6 and rigidly held to the coil mounting frame 1 by a wedge 4. The superconducting coil 3 is formed of a superconducting wire 7, and an interlayer insulation 8 formed by winding a heat hardening resin impregnated tape around the superconducting wire 7. It is wound around the coil mounting frame 1 two or more rows, and two or more layers.