ABSTRACT People with high self-criticism tend to suffer from poor mental health whereas those with high self-reassurance tend to have good mental health. Poor mental health is a great cause for concern in Japan. Many people in Japan live with mental health issues, and the suicide rate is high. In particular, the mental health of caring professionals in Japan is devastated. However, there is no established measure to assess the levels of self-criticism and self-reassurance in the Japanese language. The Forms of Self-Criticising/Attacking & Self-Reassuring Scale (FSCRS) has been actively used in mental health research. Accordingly, this study aimed to develop the Japanese version of FSCRS (J-FSCRS). 300 nurses and 120 psychologists in Japan responded to an online survey containing J-FSCRS and Depression Anxiety Stress Scales-21. Confirmatory factor analyses and a Pearson's correlation analysis were conducted. J-FSCRS is proven to be reliable to assess self-criticism and self-reassurance in the Japanese language.