A 64-year-old man visited his physician complaining of bilateral gynecomastia and left shoulder pain. Chest X-ray showed multiple bilateral masses in the lung, and he was referred to our hospital. Radiographical findings, elevation of serum total hCG, and histological findings of the cervical lymph node revealed multiple pulmonary, nodal, and brain metastases of poorly differentiated carcinoma of an unknown primary site with choriocarcinoma components. He was administered a regimen of reduced bleomycin, cisplatin, etoposide combination(reduced BEP regimen)to reduce the risk of acute respiratory failure with intra-alveolar hemorrhage related to post-chemotherapy early tumor necrosis. After chemotherapy, the tumor marker hCG levels were almost restored to normal levels, and radiography showed he had achieved a clinical partial response.