A superconducting cable is manufactured by providing spacers 12 in a plurality of cores 2 at the time of stranding of the cores 2, and removing the spacers 12 before the stranded cores 2 are housed in a thermally insulated pipe and housing the cores into the thermally insulated pipe while the strands are held in a slacked state. By means of temporal interposition of the spacers, there is easily manufactured three cores having sufficient slack to manage thermal contraction which occurs when the cores are cooled in the thermally insulated pipe.