PURPOSE: To keep a coreless induction furnace at high efficiency, and to minimize the changes of residence time and metallurgical property by constituting the furnace of a shell, a specific crucible arranged in the shell and an induction coil.

CONSTITUTION: This coreless induction furnace 10 is constructed of the shell 14, the crucible 16 arranged in the shell 14 and having an internal hollow with a depth which is remarkably smaller than a lateral direction dimension, and plural induction coils 18 arranged in the shell 14 while surrounding the crucible 16 and surrounding at least the lower part of the internal hollow. Thus, the furnace can be kept at very high efficiency, and the changes of the residence time and the metallurgical property can be minimized.