To provide a simply constituted elution device for a molten core, which makes the capacity of an elution tank small and which enables an efficient heating method for a liquid thermal medium, and an elution method.

This elution device is equipped with: the bottomed tube-shaped elution tank 12 which is placed on an installation base 10, and which is composed of a non-metallic inorganic material, that is, glass, ceramics, etc., having excellent insulation properties, heat resistance, chemical agent resistance and oil resistance; a heating body 3 which is wound around the outer periphery of the elution tank 12 in a coiled manner, and which is composed of a hollow pipe made of copper; a high-frequency power source 5 which is connected to both ends of the heating body 3 via a connection terminal part 4; and an insulative hose 14 which is coupled to both ends of the heating body 3. The hollow resin molded article 9 is supported by an implement, and installed in the elution tank 12. After lutron as a liquid thermal medium 1 is injected up to a predetermined position in the elution tank 12, heat is generated by applying a high-frequency voltage to the heating body 3, so that only the molten core 9a in the elution tank 12 can be selectively eluted.