Pulmonary actinomycosis is a rare disease entity to undergo thoracic surgery. We experienced a 49-year-old man with pulmonary actinomycosis who was admitted due to recurrent hemoptysis. Prior to admission, he was diagnosed as pulmonary tuberculosis on the basis of his clinical manifestations and chest radiological findings. The plain chest x-ray and chest computed tomography(CT) showed a cavitary lesion in left upper lobe and was given anti-tuberculous medication, but the x-ray revealed no imprcovement. He underwent left upper lobe lobectomy with segmentectomy of lower lobe and the surgical specimen showed no evidence of mycobacterial infection, but revealed sulfur granules which is a typical pathological finding of actinomycosis. He was discharged uneventfully and is scheduled to receive 6 months of antibiotic treatment.