A 46 years old male showed radiologically a single cavitary nodular lesion in right upper lung, which extended to the regional chest wall. This finding has to be made into differential diagnosis of numerous pulmonary diseases including infections such as mycobacterial, fungal or bacterial, granulomatous diseases, and neoplasms. For the definite diagnosis, fine needle aspiration biopsy guided by biplane fluoroscopy was performed. The aspirates contained several sulfur granules, in the center of which many gram positive, filamentous organisms were compactly intermingled. Such a findings was compatible with pulmonary actinomycosis. Now the lesions is cleared out by medical treatment with amoxicillin for 3 months.