A 20-year-old woman with no history of pulmonary disease had no symptom and her chest CT scans demonstrated adhesive small multiple nodules in the bronchial lung biopsy specimen showed epithelioid cell granuloma containing Langhans giant cells, therefore she was diagnosed as pulmonary mycobacteriosis caused by M. szulgai. This is the youngest case of this rare condition occurring in a healthy subject without underlying pulmonary diseases.