A 69-year-old woman presented to our hospital with productive cough. Contrast-enhanced chest computed tomography showed a mass occupying the right lower lobe. Bronchoscopy showed a brown-colored mass obstructing the right lower lobe bronchus and the pathological findings revealed malignant melanoma. Further evaluation and immunohistochemical examination provided the definitive diagnosis of primary pulmonary malignant melanoma with metastasis to the mediastinal lymph nodes, muscles, and bones. She received four courses of combination chemotherapy with nivolumab and ipilimumab, followed by three cycles of maintenance chemotherapy with nivolumab. Despite the use of chemotherapy, the tumor increased in size, and she died of a urinary tract infection six months after diagnosis. Primary pulmonary malignant melanoma is a very rare disease and there is no established treatment. Here, we describe a case of primary pulmonary malignant melanoma treated with nivolumab plus ipilimumab.