A plasma furnace comprising: a furnace body (100,200,300); and a mixed type plasma torch, wherein the furnace body (100,200,300) comprises a melting chamber for accommodating a melt, an upper surface forming the upper portion of the melting chamber with a horizontal upper surface (111,211,311)and an inclined upper surface (112,212,311)having a slope with respect to the horizontal upper surface (111,211,311), a melt discharge portion formed through a bottom surface of the melting chamber for discharging molten material therethrough, and an input apparatus (120,220,320) having a slope for inputting waste into the melting chamber, and wherein the mixed type plasma torch is provided on the inclined upper surface (112,212,312) with a slope for generating melting heat in the melting chamber, wherein the furnace body (100,200,300) further comprises: two discharge flow paths formed with a predetermined slope through the furnace body (100,200,300) so that the molten material can be easily discharged to the outside by its own weight; at least two lateral discharge gates (160,170) capable of discharging molten material at different heights on the side of the melting chamber; a heating portion (181,182) capable of heating the lateral discharge gate (160,170); and wherein the plasma furnace further comprises a discharge chamber which is provided at the side of the furnace body (100,200,300) so as to accommodate the molten material discharged along the lateral discharge gate (160,170) and have an outlet formed at the lower portion thereof; and a heating means provided so as to control the temperature inside the discharge chamber. a furnace body (100,200,300); and a mixed type plasma torch, wherein the furnace body (100,200,300) comprises a melting chamber for accommodating a melt, an upper surface forming the upper portion of the melting chamber with a horizontal upper surface (111,211,311)and an inclined upper surface (112,212,311)having a slope with respect to the horizontal upper surface (111,211,311), a melt discharge portion formed through a bottom surface of the melting chamber for discharging molten material therethrough, and an input apparatus (120,220,320) having a slope for inputting waste into the melting chamber, and wherein the mixed type plasma torch is provided on the inclined upper surface (112,212,312) with a slope for generating melting heat in the melting chamber, wherein the furnace body (100,200,300) further comprises: two discharge flow paths formed with a predetermined slope through the furnace body (100,200,300) so that the molten material can be easily discharged to the outside by its own weight; at least two lateral discharge gates (160,170) capable of discharging molten material at different heights on the side of the melting chamber; a heating portion (181,182) capable of heating the lateral discharge gate (160,170); and wherein the plasma furnace further comprises a discharge chamber which is provided at the side of the furnace body (100,200,300) so as to accommodate the molten material discharged along the lateral discharge gate (160,170) and have an outlet formed at the lower portion thereof; and a heating means provided so as to control the temperature inside the discharge chamber. two discharge flow paths formed with a predetermined slope through the furnace body (100,200,300) so that the molten material can be easily discharged to the outside by its own weight; at least two lateral discharge gates (160,170) capable of discharging molten material at different heights on the side of the melting chamber; a heating portion (181,182) capable of heating the lateral discharge gate (160,170); and wherein the plasma furnace further comprises a discharge chamber which is provided at the side of the furnace body (100,200,300) so as to accommodate the molten material discharged along the lateral discharge gate (160,170) and have an outlet formed at the lower portion thereof; and a heating means provided so as to control the temperature inside the discharge chamber.