A 68-years-old Japanese woman was hospitalized emergently because of hemorrhagic gastric ulcer. For the hospitalization period, elevated levels of white blood cell count, eosinophilic leucocyte count, serum IgE and positive MPO-ANCA were recognized. With considering clinical course and these laboratory findings, we diagnosed Churg-Strauss syndrome (CSS). Steroid therapy in combination with cyclophosphamide was effective. CSS is a rare disease, but we should discriminate this disease when we encounter gastrointestinal bleeding of unknown etiology, especially PPI-resistant gastric ulcer.