PURPOSE: To provide a treatment furnace capable of completely evaporating harmful oil by boring a hole at a portion of a metal container, such as a capacitor and a transformer, containing oil, directly applying induction heating to the metal container subjected to breaking handling to the extent that the interior of the container is allowed to communicate to the external air, and improving heat transmission to the harmful oil stuck on the inner face of the container.

CONSTITUTION: An induction heating furnace 1 is provided with a closing cover 9 having an openable means and making the interior of the furnace airtight and a venting hole 10 through the upper side face of the closing cover 9. A refractory 7 in the induction heating furnace 1 is formed to have airtightness so as to prevent evaporated gas generated from harmful oil from permeating through the refractory.