A 65-year-old woman was referred to our department of internal medicine for the examination of nephrotic syndrome. She had a history of proteinuria half a year prior. A tumor shadow was pointed out in the lower lobe of the left-sided lung and she was sent to our department. The patient was diagnosed with primary lung squamous cell carcinoma (cStage IV). In addition, she was diagnosed as having membranous nephropathy, which was the cause of her nephrotic syndrome. There was exacerbation in the primary site after the first treatment, and nivolumab was started as the second treatment. A Grade 2 creatinine level elevation was observed on the fifth day of the first course, and a renal biopsy was performed. Histopathological diagnoses were membranous nephropathy and tubulointerstitial nephritis．Nivolumab was administered every 1.5 to 4 months to maintain a partial response.