Abstract: This invention is concerned with providing a micro-wave plasma generating device of a simple structure and with good cooling effect of the insulating tube. Micro-wave plasma generating device which generates the plasma by introduction of a processing gas into the insulating tube transversing through the micro-wave waveguide in which the metal wire or the metal rod is spirally wound on and around the insulating tube. An air-blowing means is further provided at a portion of the insulating tube through which the waveguide transverses. The metal wire wound around the insulating tube may be affixed to the tube using solder.