PURPOSE: To obtain an evaporating unit so as to be small amount of tar-like waste and to be able to use for a long time even in case of using degenerating deteriorated fuel oil and the like by a method wherein a wick, constituted of copper material which operates by 400°C or more, is installed on the outer surface of a metal inner tube.

CONSTITUTION: When an electric heater 14 is conducted by electric current and the metal inner tube 6 rises at a predetermined temperature, the fuel oil is supplied from the fuel oil supplying port 9 of a fuel pump provided addition ally. a valve body 15 is opened by a solenoid. the fuel oil supplied, is supplied to the wick 13 of the surface of the metal inner tube 6 through a fuel oil supply ing pipe 8. The fuel oil is vaporized here and injected toward a mixing pipe 3 from a nozzle 11. Circumferential air is absorbed from, the circumference of the nozzle 11 by injection power and is mixed in the mixing pipe 3 to supply for a flame port 3, then, it is burnt at the upper portion of the flame port 2. The high temperature combustion gas burnt here, flows around the metal outer tube 5 of an evaporating device main body 4 and the metal outer tube 5 is heated. As a result, the wick 13 of the evaporating chamber 7 may be heated at 400°C or more.