The cause of silicosis is inhalation of silicon dioxide, or silica, in crystalline form and the subsequent reaction of lung parenchyma to the silica dust. Silicosis is popular in miners and tombstone sculptors, but rare by reports in tunnelers in Taiwan. We report a case of silicosis developed in a sapper, who participated in the tunnel construction in Kinmen during military service. Chest X-ray revealed pneumoconiosis type Ⅲ (q, 3/3) based on Guidelines for the use of ILO international classification of radiographs of pneumoconiosis (1980). He was never employed in other work with potential exposure to silica before and after military service. Therefore, this is a case of silicosis due to tunnel work.