The purpose of this study was to construct the Japanese version of the children's moral measure MY CHILD which had been developed by Kochanska(1991). In study 1, reliabilities were examined by Cronbach's alpha coefficients and retest technique. 31 items were selected, which were categorized into 2 elements, (1)Affective Discomfort consisting of guilt, concern about relationships with parents, empathy, and apology, and (2)Behavioral Control or Active Moral Regulation/Vigilance consisting of confession, internalized moral conduct, reparation, and concern about others' wrongdoing. In study 2, we measured children's morality with MY CHILD, and the age difference and the sex difference were found on several subscale scores which supported Kochanska(1993). Then, it was concluded that this scale had satisfied reliability.