Purpose: To clarify the factors that affect the family caregiver’s quality of life (QOL) of cancer patients. Methods: We conducted an internet survey including 21 items of the Japanese version CQOLC for 400 families of cancer patients in March 2012. Results: Factors that increased psychological burden were that caregivers were women, other family needed long-term care, and the patient had higher need for care. Factors that increased the family caregiver’s difficulty in their daily activities due to long-term care were caregivers are women, other family needed long-term care, caregivers did not think they had a good relationship with the patient, and the patient had higher need for care. Factors that increased financial burden were that the age of caregivers was less than 60 years, decreased of income after the patient’s diagnosis, and patients were men. Factors that increase the positive feeling for caregiving were that caregivers thought they had good relationship with the patient, and the patient’s need for care was higher. Conclusions: To reduce the burden in family caregiver of cancer patients without losing the positive feeling for caregiving would be important for both improving the family caregiver’s QOL, and to continue the care for patient in long term.