Since the local authority is enumerated in the eligible applicants for minor guardian appointment by the reformed Civil Code(Act no. 10429) in March 2011, another reformed Civil Code(Act no. 10645) included the local authority to the eligible applicants for the nomination of a person with parental responsibility in accordance with Art. 909-2 of the Civil Code in May 2011. Moreover, the other reformed Civil Code(Act no. 12777) extended the eligible applicants for the restriction, suspension and revocation of parental responsibility in accordance with Art. 923 to Art. 927-2 to the local authority. Since then, concern about child welfare issues has been increased among civil lawyers, who have traditionally dealt with disputes within family members. Even though the local authority has the power to apply to family courts on behalf of children for appointment and revocation of minor guardian and restriction, suspension and revocation of parental responsibility, the exercise of that power by the local authority has been rare. As seen in adult guardianship cases, that the local authority will be still reluctant to exercise the power granted by the Civil Code unless the power, responsibility and duties of the local authority is clearly regulated in the social welfare related statutes. In this regard, this paper premises that civil law lawyers and researchers have to focus on interrelationship between civil law and social welfare law and their distinct roles so as for the state including the local authority to discharge its own role as corporate social parents to the effect that the best interest of the child shall be the paramount consideration not only to legal parents, but also corporate social parents. Based on that premise, this paper analyses the interrelationship between civil law, criminal law and social welfare law in relation to the protection of children in need from the perspective of effectivity of the state discharging social parents’ role. This paper argues that child protection related laws are sporadic, inconsistent, and unplanned in that the content and quality of social care can be differentiated according to which law is applied. This paper argues that laws related to children in need should be reshuffled so as for the state including the local authority to effectively discharge its role as corporate social parents so that children-in-need’s emotionally, physically, and mentally healthy development can be guaranteed. In this regard, this paper suggests that the local authority should be a lead to discharge the role as corporate social parents whereas central government, prefectures(over local authority), and family courts support and advise the role of the local authority, meaning that child protection related social welfare laws should lead the whole process, which civil law and criminal law should support.