The meaning of participation in care prevention group activities may encourage continuous participation, making older adults active and healthy throughout their lives. This study developed a scale to assess the meaning of participation in care prevention group activities. It involved 427 participants in care prevention group activities (CPGAs) in Japan who filled out a self-administered questionnaire between October 2017 and February 2018. The meaning of participation was assessed using 15 items. In total, there were 379 valid responses. A factor analysis yielded two factors: “promotion of self-growth” and “enrichment of daily life”. The goodness of fit index (GFI), comparative fit index (CFI), and root mean square error of approximation (RMSEA) were satisfactory (GFI = 0.923; CFI = 0.960; RMSEA = 0.073). Cronbach’s α was 0.939 for the entire scale. The scale scores were significantly correlated with scores of the social activity-related daily life satisfaction scale and Ikigai-9. The scale’s reliability and validity were confirmed, indicating its usability for promoting care prevention efforts.