A 41-year-old female with progressive dyspnea was admitted to Chiba University Hospital. Pulmonary function tests showed she had significant obstructive ventilatory impairment. Chest high-resolution CT showed mosaic shadow by air trapping, and serum MPO-ANCA (myeloperoxidase antineutrophil cytoplasmic antibody) was high (133 U/ml). Moreover, transbronchial lung biopsy revealed hemosiderin-laden alveolar macrophages and granuloma in alveolar space and capillaritis accompanied with deposition of fibrin. She was suspected to be suffering from bronchiolitis obliterans (BO) by ANCA-associated vasculitis. Dyspnea, MPO-ANCA, and were improved by the administration of glucocorticoids and immunosuppressant, but FEV₁ was not improved. BO by ANCA-associated vasculitis without other organ dysfunctions was a rare case.