The reliability and validity of the Subjective Burden Scale (SBS) were investigated in 255 Japanese family caregivers of elderly relatives with dementia. Values of the Cronbach's alpha reliability, split-half reliability (r), and test-retest reliability (r) were .87, .80, and .72, respectively. The SBS score was significantly positively correlated with the degree of mental health, which was assessed with the Japanese version of the 60-item General Health Questionnaire (r = .41). The family caregivers who gave up the caregiving of their relatives showed significantly higher SBS scores than those who did not. The SBS scores for caregivers indicated satisfactory predictive validity both in the degree of their mental health and in the prospects of family caregiving about 6 months later. These findings suggest that the SBS is adequately reliable and valid and can be used to assess the subjective burden of Japanese caregivers.