An 82‒year‒old female presented to our hospital with abdominal fullness and loss of appetite. Abdominal computed tomography revealed a cholangiocarcinoma(Stage Ⅳ)with liver metastases and multiple lymph node metastases. In addition, we found a left ovarian teratoma(approximately 33 cm in diameter)occupying most of the abdominal cavity. She did not want an aggressive treatment for cholangiocarcinoma, but hoped to receive the best supportive care. She was treated with a fentanyl patch, although there was no symptomatic improvement. We explained that resection of the giant ovarian tumor may improve the symptoms. As a result, she accepted the surgery. The laparotomy was performed, and a left ovarian tumor(approximately 10,600 g in weight)was resected. Operation time was 2 hours and 35 minutes, and the amount of blood loss was small. No postoperative complications were observed. She started oral intake at POD 2. The abdominal symptom was relieved by the surgery, and she was discharged to her own home on POD 12. She was readmitted on POD 46 for general malaise, and died of advanced cholangiocarcinoma on POD 66. It was suggested that the QOL may be improved by resecting symptomatic benign tumors even in terminal cancer patients.