PURPOSE: To supply oxygen and treat oxygen thermally, to introduce oxygen sufficiently and to obtain a superconductor coil having excellent characteristics easily by repeating the decompression of a configuration atmosphere and replacement by oxygen gas.
CONSTITUTION: A superconductor wire rod in which the inside of a metallic tube is filled with oxide superconductor powder is wound to a coil shape required. A wound body acquired by a winding process is thermally treated while repeating bringing to the state of decompression of at least a configuration atmosphere and the supply of oxygen gas as the gas is left as it is brought to the state of normal pressure. A perovskite type oxide superconductor having a high critical temperature and containing a rare earth element is used as an oxide superconductor. Consequently, the oxide superconductor can be supplied uniformly with oxygen. Accordingly, a superconductor coil having excellent characteristics is obtained easily.