A 73-year-old male was admitted to our hospital because of abnormal shadow in the lung field. The pathological report of the percutaneous needle lung biopsy specimen under the CT scan was suggested lymphoma (lymphomatoid granulomatosis suspected), and the right middle lobectomy was performed. Histological and immunohistochemical examinations of the operative specimen revealed B-cell type malignant lymphoma (diffuse pleomorphic lymphoma, large cell type, high grade lymphoma). Primary pulmonary malignant lymphoma is a rare disorder, and it is difficult utilized to distinguish between true malignant lymphoma and lymphomatoid granulomatosis, or pseudolymphoma. Anyway, the first choice of the treatment is surgical excision, because of its satisfactory prognosis.