A diesel particulate filter trap comprising: - a filter that is connected to an exhaust conduit at a side opposite to that of an engine; - a plasma burner that is provided in the exhaust conduit between the engine and the filter, that comprises a fuel inlet (122, 222, 322, 422, 532, 622) that supplies fuel and a flame vent (128, 228, 328, 428, 534, 628) that projects a flame by a plasma discharge, and that heats exhaust gas; - and a fuel inflow conduit (112, 212, 312, 412, 503, 612) that connects the fuel inlet and a fuel tank, wherein the plasma burner includes: - a reaction furnace (160, 260, 360, 460, 510, 660); - an electrode (150, 250, 350, 450, 520, 650) that is provided within the reaction furnace while sustaining a distance from an internal wall of the reaction furnace, the plasma discharge being generated between the electrode and the internal wall of the reaction furnace, wherein the reaction furnace comprises an exhaust gas inlet (194, 294, 494, 533) that is formed at one side of the reaction furnace to supply the exhaust gas, thereby mixing fuel that is injected into the reaction furnace through the fuel inlet with the exhaust gas and inducing the formed mixed gas between the reaction furnace and the electrode, characterized in that; - the reaction furnace (160, 260, 360, 460, 510, 660) is provided within the exhaust conduit; - the flame vent (128, 228, 328, 428, 534, 628) is formed at opposite side of the exhaust gas inlet (194, 294, 494, 533) to project the flame by the plasma discharge of the mixed gas; - and in that the reaction furnace further comprises: - an external cylinder that is exposed within the exhaust conduit; and - an internal cylinder that is provided within the external cylinder to form a preheating passage between the internal cylinder and the external cylinder, wherein a preheating passage that is connected to the fuel inflow conduit (112, 212, 312, 412, 503, 612) to preheat the supplied fuel, wherein, at the exhaust gas inlet side, the internal cylinder forms an inner surface of a cone that is progressively opened toward the exhaust gas inlet side. - a filter that is connected to an exhaust conduit at a side opposite to that of an engine; - a plasma burner that is provided in the exhaust conduit between the engine and the filter, that comprises a fuel inlet (122, 222, 322, 422, 532, 622) that supplies fuel and a flame vent (128, 228, 328, 428, 534, 628) that projects a flame by a plasma discharge, and that heats exhaust gas; - and a fuel inflow conduit (112, 212, 312, 412, 503, 612) that connects the fuel inlet and a fuel tank, - a reaction furnace (160, 260, 360, 460, 510, 660); - an electrode (150, 250, 350, 450, 520, 650) that is provided within the reaction furnace while sustaining a distance from an internal wall of the reaction furnace, the plasma discharge being generated between the electrode and the internal wall of the reaction furnace, - the reaction furnace (160, 260, 360, 460, 510, 660) is provided within the exhaust conduit; - the flame vent (128, 228, 328, 428, 534, 628) is formed at opposite side of the exhaust gas inlet (194, 294, 494, 533) to project the flame by the plasma discharge of the mixed gas; - and in that the reaction furnace further comprises: - an external cylinder that is exposed within the exhaust conduit; and - an internal cylinder that is provided within the external cylinder to form a preheating passage between the internal cylinder and the external cylinder, wherein a preheating passage that is connected to the fuel inflow conduit (112, 212, 312, 412, 503, 612) to preheat the supplied fuel, wherein, at the exhaust gas inlet side, the internal cylinder forms an inner surface of a cone that is progressively opened toward the exhaust gas inlet side. - an external cylinder that is exposed within the exhaust conduit; and - an internal cylinder that is provided within the external cylinder to form a preheating passage between the internal cylinder and the external cylinder,