1. In an administrative litigation case, even if a participant does not fall under a third party’s participation as provided by Article 16 of the Administrative Litigation Act, a participant may participate if the participant satisfies the requirements for participation in the lawsuit, and its nature is deemed as a co-litigation assistance (see, e.g., Supreme Court Decision 2011Du13729, Mar. 28, 2013). On the other hand, an intervention in the lawsuit under the Civil Procedure Act may be an objection that has an interest in the outcome of the lawsuit (see, e.g., Article 71 of the Civil Procedure Act). The term “interested interest” refers to legal interest, and thus, the term “interested interest” refers to a case in which res judicata or executory power of the judgment in the lawsuit, or even if the effect of the judgment in the lawsuit in question does not directly affect the judgment in question, it refers to a case in which the legal status of the intervenor is determined at least on the premise of the judgment (see, e.g., Supreme Court Decision

In an administrative litigation seeking the revocation of corrective measures ordered by the Fair Trade Commission, where the relevant corrective measures include the suspension or prohibition of a specific act against the other party, whether the relevant enterpriser can continue such specific act by a judgment in the lawsuit depends on whether or not the relevant enterpriser can continue such act. Therefore, the other party to the act is determined as a legal status by a judgment, and thus, he/she may participate in the aforementioned administrative litigation in order to assist the Fair Trade Commission

2. According to the records, the re-appellant, who is a business association consisting of dental license holders, applied for the participation of the re-appellant on behalf of the Fair Trade Commission, who is the counterpart to the act of restricting the use of dental services, on the ground that the re-appellant restricted the use of “○○○ website”, which is a network dental service provider, to the members of the re-appellant. The Fair Trade Commission filed a lawsuit to revoke the above corrective order against the re-appellant. While the lawsuit is pending, the re-appellant filed a lawsuit against the Fair Trade Commission to revoke the above corrective order, etc., and the re-appellant, who is the counterpart to the act of restricting the use of dental services, filed an application for participation

Examining the record in light of the aforementioned legal principles, it is justifiable that the court below allowed the applicant for intervention in the case where the corrective order was the counter-party to the act prohibited by the use restriction against the re-appellant, such as the corrective order filed by the re-appellant against the Fair Trade Commission. Contrary to the allegations in the grounds of reappeal, the court below did not err by misapprehending the legal principles on “legal interest” or “any significant delay in the litigation procedure,” or by failing to exhaust all necessary deliberations.

3. Therefore, the reappeal of this case is all dismissed. It is so decided as per Disposition by the assent of all participating Justices on the bench.

Justices Ko Young-han (Presiding Justice)