Mass examination of the ladorers in wood and products industries was conducted. The workers showing abnormal chest x-ray findings were over 40years of age and had worked longer than 20 years in these industries. The abnormal x-ray findings were linear and small opacities. From these observation, it is likely that the abnormal findings of chest x-ray films were associated with wooden dust. The experimental studies by infusing paulowina dust into the lungs of rats showed the foreign body granuloma. These epidemiological and experimental studies suggest that wooden dust. Namely paulownia, causes pneumoconiosis in the wood workers.