Allergic bronchopulmonary mycosis (ABPM) is a pulmonary hypersensitivity disease mainly caused by Aspergillus fumigatus. The mainstay treatment for ABPM is systemic corticosteroid therapy. A 25-year-old man presented with pulmonary infiltrates. His peripheral eosinophil, total serum IgE, and serum Aspergillus-specific IgE levels were elevated. The patient tested positive in a skin test for Aspergillus. However, sputum cultures revealed a Curvularia lunata infection. We therefore diagnosed ABPM possibly caused by C. lunata, which is rare in Japan. The clinical state of the patient improved under observation. Identification of the causative fungus is an important aspect of the ABPM diagnosis.