A 58-year-old female was admitted to our hospital because of fever and dyspnea on exertion. She has been working in the factory making Pholiota nameko for 8 years. Her chest X-ray revealed diffuse linear and fine nodular shadows in both lower lung fields. Hypoxemia was seen on blood gas analysis. Bronchoalveolar lavage (BAL) and transbronchial lung biopsy (TBLB) were performed. Differential cell count of the BAL fluid showed lymphocytosis and CD4/8 was decreased. TBLB specimens revealed bronchioloalveolitis. Precipitins against Trichosporon cutaneum were detected by Ouchterlony method. These findings are compatible with hypersensitivity pneumonitis, and Trichosporon cutaneum may have been causative antigen in this case. Trichosporon cutaneum is often detected in the Japanese summer-type hypersensitivity pneumonitis. This case suggests that Trichosporon cutaneum is one cause of hypersensitivity pneumonitis in workers at factories making Pholiota nameko.