A 57-year-old man had right supraclavicular, right hilar, and mediastinal lymphadenopathy in chest computed tomography (CT) during follow-up after colon cancer surgery. Lymph node biopsy specimens showed no significant finding. He had multiple nodules and patchy shadows in both lung fields 15 months later. A surgical lung biopsy was performed. Pathological examination revealed giant cell interstitial pneumonia. His occupation turned out to be a metal grinder. Since cobalt was detected in an elementary analysis of lung tissue, his illness was diagnosed as hard-metal lung disease. The multiple nodules and patchy shadows on chest CT disappeared by his wearing a mask. From the immunostaining results and pathological findings, lymphadenopathy was estimated to be due to inhalation of hard metal. To our knowledge, this is a rare case of hard-metal lung disease showing multiple patchy shadows preceded by lymphadenopathy.