The patient was a 60's-year-old man, who was incidentally pointed out a coin lesion in the right lung by chest radiogram. Chest computed tomography showed a round-shaped, well defined nodule of 2.5 cm in size in the right S1. Positron emission tomography did not show the accumulation of fluorodeoxyglucose in the nodule. We considered the tumor to be benign, but the patient chose surgical treatment. Partial resection of the lung was performed by thoracoscopic surgery. Histopathological diagnosis was human pulmonary dirofilariasis.