Sadatoshi, one of the authors, had reported previously that he had found 26% of electric welders at a certain heavy industrial plant suffered from pneumoconiosis by roentgenological examination. In this time investigation was done upon 78 electric welders carrying pneumoconiosis without pulmonary tuberculosis and the result was as follows: 1) Chest X-ray findings approved granulated type. No fibrosis, tendency of confluence, emphysema and eggshell calcification. Changes in hilus could not be found at the begining. 2) No visible changes in blood findings. Except, as the type advanced, a tendency of a slight decrease in neutrophil leukocytes and increase in lymphocytes could be seen. 3) No remarkable changes admitted in lung vital capacity and maximum ventulating volume. Expiratory impediment appeared in the third type. 4) Though welding dust contains SiO(2), welder's pneumoconiosis is innocent compared with silicosis. It also seems a little different from siderosis and so is suitable to classify it as "welder's Pneumoconiosis". 5) Occupational career should be cared when taking routine X-rayphotographs.