PURPOSE: To obtain a stable X-ray source by providing an X-ray generator, which is based on quantum-ray irradiations, with a function of removing matters deposited on an X-ray dischaering window and so forth and on the inner wall of an X-ray device by means of gas and plasmas.

CONSTITUTION: In the figure, the symbol 15 represents an X-ray; the symbol 16, evaporating Al particles; the symbol 17, an X-ray discharging window made of Be; the symbol 18, a vacuum case made of quartz; the symbol 19, a vacuum valve; the symbol 20, a gas introducing valve; and the symbol 21, an RF oscillating coil. Vapor deposition Al films formed on the inner walls of the vacuum case 18 and window parts 12 and 17 due to vapored Al particles discharged from a target, are removed as Al2Cl3 by exciting Cl2 gas introduced from the valve 20 into plasmas by means of an RF coil 21 while maintaining the internal pressure of the case 18 at 1Torr by means of the valve 19. As a result, any X-ray reduction which might be caused during a multiple-irradiation can be prevented.