An apparatus for demolishing an oil-containing industrial waste object, includes a turntable for supporting thereon of an oil-containing industrial waste object, a sealed enclosure mounted above the turntable for gas-tightly enclosing the industrial waste object, a fluid pumping device for sucking a fluid medium out from the sealed enclosure, and a plasma arc torch fitted inside the sealed enclosure for radiating the industrial waste object with a plasma. After the fluid medium within the sealed enclosure has been sucked out by the fluid pumping device, an inert gas is supplied into the sealed enclosure through an inert gas supply port. The industrial waste object is then irradiated by a plasma from the plasma arc torch while being rotated together with the turntable, to thereby cut the industrial waste object horizontally.