We reported a case of fibrosing alveolitis following Legionella pneumonia. A 62-year-old man was admitted to our hospital with fever after a visit to a hot spring. Chest X-ray films on admission demonstrated air-space consolidation in the right lower lung. Legionella pneumonia was diagnosed because the patient had elevated serum antibody to Legionella pneumophila serogroup Ia and tested positive for urinary antigen. Although he was initially treated with rifampicin and erythromycin, he experienced drug-induced eruptions. Antibiotic therapy was accordingly changed to clarithromycin, levofloxacin, and minocycline, which together alleviated the patient's clinical symptoms but delayed radiologic regression. Chest X-ray films 2 months after the onset of illness revealed diffuse ground-glass opacities and progressive reduction of volume in the right lung. Long-term corticosteroid treatment was required. Three and half months after disease onset, fever recurred with the appearance of interstitial shadows in the left lung and positive tests for urinary antigen. Increasing the corticosteroid dose resolved the patient's symptoms.