PURPOSE: To obtain a heating furnace in which a material for an oxide superconductor is heated and a temperature gradient from one end toward the opposite side is properly given to the material regardless of the thickness of the material by providing a cooling device on the furnace bed to cool the end of the material.

CONSTITUTION: A heating furnace 11 is surrounded with heating device 10 and a material 12 for an oxide super-conductor, etc., is placed on a furnace bed 13 in the furnace 11. A liquid or gas cooling medium 14 flows through the inside of the furnace bed 13, so that the material 12 is cooled from below and given a temperature gradient. Therefore, after an oxide super-conductor molding material is heated and melted, a slow-cooling step in which the molding material is slowly cooled drown with an one-way temperature gradient maintained is effectively carried out.