Background: Japan and other nations are experiencing rising demands for care, owing to declining birth rates and aging populations. This particularly affects compound caregivers, people who provide informal care for multiple individuals. Compound caregivers face unique challenges and higher risks of physical and mental health problems. However, existing self-care scales do not cover their needs. This cross-sectional study aimed to develop and validate the Self-Care Scale for Compound Caregivers (SCSCC) to assess specific self-care practices and promote targeted support. Methods: A cross-sectional study was conducted through an online survey of 400 compound caregivers. Reliability was assessed via item analysis, exploratory and confirmatory factor analyses, and Cronbach’s alpha. Criterion validity was evaluated using a self-rated health scale. Results: Overall, 400 compound caregivers participated in the study. After item analysis, we excluded nine items, leaving eight for factor analysis. Exploratory factor analysis revealed a single-factor structure explaining 51.5% of the variance. Confirmatory factor analysis showed a good model fit after modifications (goodness of fit index = 0.964, adjusted goodness of fit index = 0.932, comparative fit index = 0.980, root mean square error of approximation = 0.054). The final version of the SCSCC demonstrated strong internal consistency (Cronbach’s alpha = 0.859) and was positively correlated with self-rated health (r = 0.387, p < 0.001). Conclusions: The SCSCC is a reliable tool for assessing self-care in compound caregivers, supporting health promotion, interventions, and policies to improve their health within the community care system.
