In the cited article, an x‐ray source developed for extended x‐ray absorption fine structure measurements is described. After the publication, the authors have further improved the performance by employing a compact rotating anode and by optimizing an electron gun. This new x‐ray generator provides high tube current of 1100 mA at 18 kV with the narrow focal spot of about 0.1 mm in width. Extremely intense monochromatic x rays, which are completely free from higher order reflections, are now available in a laboratory, and the measurement time required for a practical sample has been shortened to less than 2 h.