To provide an electrode insulation structure of a plasma arc type melting furnace which surely prevents generation of stray current by enhancing insulation performance of a sleeve surrounding an electrode of the plasma arc type melting furnace.

In the electrode insulation structure of the plasma arc type melting furnace 10 wherein the main electrode 11 is inserted into the furnace body via the insulative sleeve 25, an annular slit 26 concentric with the sleeve and having a header 27 is arranged in the sleeve 25. An inert gas introducing means including a compressor 20 to inject the inert gas to the inside of the furnace from the slit 26 is also provided. The inert gas is uniformly injected to the inside of the furnace via the header 27 by the inert gas introducing means.