국민건강보험법상 부당이득징수처분에 대한 행정법적 통제 - 공법상 부당이득반환청구권의 관점에서 -

In recent years, there has been an increasing number of disputes regarding unjustified claims for healthcare benefits costs, primarily attributed to the aging population and the consequent rise in expenditures on such benefits. In response, the National Health Insurance Service (NHIS) has actively pursued the collections of unjust enrichment under the National Health Insurance Act, aiming to protect the financial stability of healthcare. However, this initiative has raised concerns about excessive collection, highlighting the need for administrative legal control to ensure that the collection process adheres to the principle of the rule of law in administration. This article conducts an analysis of a recent judgment by the Supreme Court, which recognized the illegality of collecting the entire costs of healthcare benefits in a case involving the mutual use of medical facilities. It examines this judgment from the perspective of the claim for restitution of unjust enrichment under public law, providing insight into the appropriate implementation of administrative legal control. The claim for restitution of unjust enrichment under public law is an independent institution within public law derived from the principle of legality of administration. Considering that the collection of unjust enrichment under the National Health Insurance Act possesses the characteristics of the claim for restitution of unjust enrichment under public law, the principle of legality of administration plays a pivotal role in interpreting the grounds and extent of the collection of unjust enrichment. In specific cases, it becomes crucial to identify the statutes that serve as the criteria for determining the legality or illegality of benefits among various statutes. In the judgment, the Supreme Court properly concluded that the National Health Insurance Act and its subordinate regulations, possessing the force of law, constitute the criteria for determining the legality of benefits. Additionally, the court established clear boundaries for unjust enrichment, specifically focusing on healthcare benefits costs that fell within the scope of violations under the aforementioned laws. Furthermore, the court acknowledged the illegality of collecting healthcare benefits costs that contravened other laws. Thus, by delineating the scope of unjust enrichment under public law in accordance with the principle of legality of administration, this judgment effectively exercised administrative legal control over the issue of excessive collection under the National Health Insurance Act.