Background. Pneumoconiosis is defined based on the fibroproliferative changes in the lung caused by inhalation of dust, such as polishing powder containing silica. Cases of dental technician's pneumoconiosis were described as early as 1939. Case. A 40-year-old male dental technician was referred to us because of nodular infiltrates on a chest radiograph. He complained of having a dry cough. He had been working as a dental technician for the past 15 years and had been engaged in polishing dental metals. Computed tomography revealed centrilobular nodules, predominantly in the upper lung fields. We performed bronchoalveolar lavage and a transbronchial lung biopsy of the right upper lobe. Biopsy specimens showed dense fibrosis with pigmented macrophages. Under a polarizing microscope, refractile materials of various sizes were observed, suggesting that minerals were present in the affected lung tissues. We performed a microanalysis of minerals in the affected lung tissue and bronchoalveolar lavage fluids using an energy-dispersive X-ray analytical spectrometer. In addition, five raw materials used in his dental laboratory were similarly analyzed. A mineral analysis revealed that the affected lung tissues and bronchoalveolar lavage fluids contained metals such as aluminum, silicon, chromium, and cobalt, which were consistent with the dental materials that the patient had handled in the laboratory. Conclusion. We diagnosed this patient with pneumoconiosis caused by inhalation of dental metals. This is the first reported case of pneumoconiosis in a dental technician wherein the metallic particles in the lung were matched with the inhaled dental materials present in the dental laboratory.