PURPOSE: To obtain the cooling device, having no radio leakage, which will be easily assembled by a method wherein the transistor located at the high frequency radio wave generating unit is fixed on a heat conducting pipe through the intermediary of a heat diffusing plate, the transistor is connected to all the heat radiating fins excluding those located on the main body, and the heat radiating fins are fixed to the wall face of the main body using pipe fittings.

CONSTITUTION: The transistor 12 is installed on the outer wall 22 located inside the side wall 8 of the main body of a heating chamber 27 through the intermediary of a metal fitting 23, a heat radiating plate 13b and a heat diffusing plate 13a, and a high frequency radio wave generating unit is composed of an electrode 15, strip wires 16W19 and an earth electrode. The generated heat of the transistor 12 is guided to the heat radiating fin 11 located outside the side wall 8 by the help of a heat conducting pipe 10 and a thermo-operating medium 26. The pipe 10 is fixed on the side wall 8 using metal fittings and screws 21. As a result, the radio leakage can be prevented and the assembling work of the device can also be simplified.