The purpose of this study is to analyse whether Article 63-2 of the National Pension Act, which authorizes the administration to decide on the reduction of pension payments for pensioners engaged in income activities, is constitutional. In this paper, it raises the question of whether Article 63-2 of the National Pension Act conforms to the principle of parliamentary reservation based on the Constitution. For this purpose, we use the literature research method which analyzes using the laws related to the subject, the precedents of the Constitutional Court, and the secondary literature. The research results are as follows. Article 63-2 of the National Pension Act entrusts the administration with the power to determine the level of income that is the criterion for reducing pensions that are related to the realization of essential basic rights such as property rights and freedom, which violates the principle of parliamentary reservation. This violates the Constitution by violating the basic rights guaranteed by the Constitution.
At the same time, the National Pension Act entrusts the executive with the authority to determine income levels without specific purpose, content, or limitation of delegation, which is contrary to the Constitution, which prohibits comprehensive delegation. In contrast, the current Military Pension Act and the Public Officials Pension Act, through the revision of the law in accordance with the Constitutional Court's unconstitutional ruling, regulate the level of income in the law, which is the standard for pension cuts for pensioners engaged in income activities. Therefore, the applicable provisions of the National Pension Act should be amended in the form of direct discipline in the law, as in the Military Pension Act and the Public Officials Pension Act.