Although many studies have investigated factors that affect family caregiving burden in Japan and other countries, they have produced inconsistent results. The purpose of the current study was to explore which factors influence the burden of caregivers who cared for elderly family members. 60 male and 298 female family caregivers (aged range from 30 to 93) participated in the study. They completed questionnaires measuring caregiver and care recipient characteristics, caregiving environment and positive appraisals of caregiving support, and the Cost of Care Index measuring caregiving burden. It was found that caregivers with worse mental health (caregiver characteristics) and lower satisfaction with family members (positive appraisals of caregiving support) showed the greater levels of caregiving burden. Several suggestions for future research are provided in this area.