MASS SPECTROSCOPE

PROBLEM TO BE SOLVED: To easily clean an ion lend of a spectroscope by providing a heating means at a member constituting the ion lens. SOLUTION: An electrode plate 20a which is one of constituent members of a plurality of ion lenses 20 of a mass spectroscope is held in an insulating manner to the wall surface of a mass filter chamber by a holder 20b. A converging power source 30 and a high heat conductive ceramic 34 wound with a heating nichorome wire 33, are fitted to a projecting part provided at the lower part of the electrode plate 20a. A heating power source 31 is connected to the nichrome wire 33 through a relay 32. In the case of the ion lenses being soiled by the continuation of analysis to cause the necessity of cleaning, the converging power source 30 is switched off to close the relay 32, and a current is applied from the heating power source 31. When a current flows to the nichrome wire 33, the high heat conductive ceramic 34 is heated, and the whole metallic electrode plate 20a is heated. Soil stuck to the ion lenses is gasified by heating and removed to the outside of a device by a vacuum pump.