The control of information about oneself has emerged as the most sensitive issue both personally and nationally in a digital information society. In the digital information society, the right to informational self-determination is very likely to emerge as a fundamental constitutional right to be the cornerstone of maintaining a free democratic system. As a guardian of constitutional rights, the Korean Constitutional Court has maintained an appropriate balance between guaranteeing the right to informational self-determination and social safety. This paper examines how the Constitutional Court allows restrictions on the right to informational self-determination by analyzing the details of the four-step review of the principle of prohibition of excessive restriction on cases of violation of the right to informational self-determination. Even if some flaws are often found in the process of the argumentation, the Constitutional Court's credit for properly balancing the right to informational self-determination and social safety as public interest should not be underestimated.