PURPOSE: To reduce noises to be made from a high-frequency crucible type induction furnace by a safe method of inserting an easily detachable reinforcing member between a joint steel plate and a lower furnace frame in a high-frequency crucible type induction furnace comprising a joint steel plate holding an induction heating coil on the outer periphery thereof, a lower furnace frame holding the joint steel plate and an upper furnace frame fixing the lower furnace frame.

CONSTITUTION: A joint steel plate 4 is pressed, on the upper outer periphery thereof, toward the central part of a furnace by an annular reinforcing member 101, a bolt 102 and a spacer 103, and a patch 4a of the joint steel plate 4 and a bolt 8a for mounting the patch 4a to a lower furnace frame 8 function to check the joint steel plate 4 from moving toward the central part of the furnace. Thus, the joint steel plate 4 and the lower furnace frame 8 are integrated together. A plurality of sets of the annular reinforcing member 101, bolt 102 and spacer 103 may be provided in addition to those provided at the upper part of the joint steel plate 4, and, further, a beam for checking the annular reinforcing member 101 from being detached or moved is provided.