To provide a plasma arc melting furnace capable of performing uniform melting treatment of an object to be treated and further performing melting treatment of combustibles while suppressing the consumption of an electrode caused by corrosive gas without generating a stray current in a furnace body.

This plasma arc melting furnace 10 maintaining the interior of the furnace at a high temperature by plasma arc generated between electrodes, has a plasma arc generating part for generating plasma arc 30 by applying voltage between a main electrode 13 and a nozzle part 14 disposed to envelop the main electrode, by a DC power supply 16, and a radiation region 18 formed by allowing the plasma arc 30 to flow into the furnace by operating gas 15 led between the main electrode 13 and the nozzle part 14, and is constituted so that the melting treatment of waste 20 is performed in the radiation region 18.