We report the first case of pulmonary Corynebacterium ulcerans infection mimicking Churg-Strauss syndrome (CSS). Productive cough, fever, general fatigue, and weight loss developed in a 50-year-old man. Laboratory data revealed prominent eosinophilia and elevated serum IgE. On chest images, multiple nodules and cavities were predominantly detected in the right lung. Histopathologic examination showed necrotizing granulomas and vasculitis with massive eosinophilic infiltration identical to the findings seen in CSS; however, clusters of Gram-positive, coryneform rods were observed in the alveolar spaces. A toxigenic strain of C ulcerans was isolated from lung tissue. The patient was treated with antibiotics, and a favorable clinical course ensued.