On the basis of national security and territorial integrity, can the state regulate the use of land and buildings around important defense facilities or on border islands? In response, on June 16, 2021, Japan promulgated ‘Important Land Survey Regulation Act.’ In enacting the Important Land Survey Regulation Act, the Japanese government suggested land acquisition in a specific area by foreign capital as a basis for legislation. Due to the cases of land acquisition in a water source, defense facilities, or border islands, anxiety among Japanese residents and the people is growing. As a background of legislation, the Important Land Survey Regulation Act refers to ‘concerned’ foreign capital and state. It is primarily considering Korea and China as regulatory targets. The Important Land Survey Regulation Act is a regulation law based on the maintenance of the base of national life, maritime sovereignty, and national security. In the future, I think the Important Land Survey Regulation Act will have a direct or indirect effect on Korea. From a national security perspective, laws that regulate direct investment in corporate purchases also exist in the United States and Japan. However, regulations on real estate transactions have recently been introduced from the perspective of national security. In the United States, the Foreign Investment Risk Review Modernization Act (FIRRMA) enacted in August 2018 is a representative law. Real estate transactions are being conducted as a subject of review by the US Foreign Investment Committee (CFIUS). From a national security perspective, Japan is reviewing the case of the United States, which regulates the sale of real estate. However, problems with the bill were pointed out in the process of enacting the Important Land Survey Regulation Act. The issue of unconstitutionality of the Important Land Survey Regulation Act was also raised. In this study, I reviewed the issues and the contents of the law in the legislative process of the Japanese National Assembly : the purpose of legislation and the existence of legislative facts, the subject of regulation and delegation of legislation, forest and water sources, enforcement decree and delegation legislation, resident movement regulation, designation of special zones, and pre-reporting system, etc. The following matters were reviewed on the issue of unconstitutionality inherent in the Important Land Survey Regulation Act : legislative purposes and the absence of legislative facts, violation of the principles of parliamentary legislation, principle of criminal justice, recommendations and orders and criminal penalties, land use investigation and personal information, privacy rights, freedom of thought and conscience, self-denial rights, property rights and compensation systems, etc. The Important Land Survey Regulation Act, like FIRRMA in the United States, is based on national security, Japan primarily aims to protect Japan’s Self-Defense Forces facilities and U.S. military facilities. To this end, ownership and use, and transactions of land and buildings in a specific area are regulated. Second, however, it is a law to prepare for border disputes or maritime disputes between Japan and China, Japan and Russia, Korea and Japan. From the perspective of borders, territories, and maritime sovereignty, the Republic of Korea needs to establish new border protection measures for uninhabited islands and islands.