This study discusses the pattern of development of child-related policies, particularly in recent years. The Liberal Democratic Party (LDP) lacks interest in public engagement in child-related issues, whereas Komeito, the recent coalition partner of the LDP, has been the driving force of recent developments. The study investigates the historical development of three child-related policies: namely, child allowance, childcare services, and the facilitation of work–life balance of employees, and discusses the role of Komeito in the recent coalition government. An analytical model is provided to explain why Komeito was active in the development of child allowance, but not other policies. On the whole, the participation of Komeito in the coalition government seems to give impetus to the development of child-related polices, but the scope of that party's behavior is constrained, due to its position as a minor partner in the coalition government.