The present invention relates to a plasma furnace which can efficiently treat various types of waste in large amounts. The plasma furnace comprises a melting chamber 101 for accommodating a melt, an upper surface forming the upper portion of the melting chamber 101 with a horizontal upper surface 111 and an inclined upper surface 112 having a slope with respect to the horizontal upper surface 111, a melt discharge portion 130 formed through a bottom surface of the melting chamber for discharging molten material therethrough, and an input apparatus 120 having a slope for inputting waste into the melting chamber 101, and the mixed type plasma torch 191, 192 provided on the inclined upper surface 112 with a slope for generating melting heat in the melting chamber 101.