A 79-year-old male was admitted to our hospital because of fever and swelling of both lower limbs with tenderness. Magnetic resonance imagery of the thighs revealed high intensity of the fascia in the short T1 inversion recovery image, consistent with inflammation of the fascia. Laboratory examination showed elevated C-reactive protein and MPO-ANCA titer, but absence of elevated creatine kinase. After admission, he complained of hemoptysis, and chest computed tomography findings revealed diffuse consolidation with interlobular septal thickening. A bronchoscopy was done; bronchiolar lavage showed bloody, and cytology by bronchoalveolar lavage fluid showed hemosiderin-phagocytic macrophages, consistent with alveolar hemorrhage. Transbronchial lung biopsy revealed organization with a few granulomas. Therefore, we diagnosed him as having microscopic polyangiitis (MPA). We treated him with combination therapy, including methylprednisolone pulse therapy and azathioprine, and his condition gradually improved. Fasciitis in cases of ANCA-associated vasculitis, including MPA, is very rare. We concluded that we should take MPA into consideration in cases that present with fasciitis.