The present study developed a Japanese version of the Strength Knowledge Scale (SKS: Govindji & Linley, 2007), and investigated its reliability and validity. The participants were Japanese university students. An exploratory factor analysis showed a one-factor structure. Internal consistency and test–retest reliability were sufficient. The SKS was associated with subjective well-being, self-esteem, characteristic self-efficacy, character strength, and identity. The findings showed that the Japanese version of the SKS had substantial reliability and validity. Furthermore, in this study the SKS was related to holding strengths and identity.