2. The case is remanded to the Seoul Administrative Court.

The following facts are significant in this Court:

A. On July 15, 2009, the Plaintiff filed the instant lawsuit seeking revocation of the approval of the implementation of an urban environment rearrangement project against the Defendant’s Intervenor on May 15, 2009.

B. On March 16, 2010, the Plaintiff’s Intervenor filed an application for intervention with the intent to intervene in the instant lawsuit in order to assist the Plaintiff in winning the lawsuit. On March 26, 2010, the Defendant’s Intervenor submitted a written objection against the Plaintiff’s intervention. On April 27, 2010, the first instance court considered both opinions as to the Plaintiff’s motion for intervention as to the Plaintiff’s motion for intervention as to the Intervenor’s motion for intervention as of the fifth date for pleading, and decided to permit the application, deeming the application for intervention as meeting the requirements stipulated in Article 71 of the Civil Procedure Act, and the decision became final and conclusive as is.

C. On July 29, 2010, the Plaintiff withdrawn the instant lawsuit, and the Defendant and the Intervenor joining the Defendant consented to the withdrawal of the lawsuit by the Plaintiff on the same day.

D. On July 29, 2010, the Plaintiff’s Intervenor filed an application for the designation of date on July 30, 2010, alleging that the Plaintiff’s filing of the lawsuit on July 29, 2010 was invalid.

2. The plaintiff assistant intervenor's assertion

The supplementary intervenor asserts that the supplementary intervenor's participation in the plaintiff's supplementary intervenor is a co-litigation participation as provided by Article 78 of the Civil Procedure Act, so this case is applied mutatis mutandis by Article 67 (1) of the Civil Procedure Act. Therefore, the plaintiff's participation, without the consent of the supplementary intervenor, has no effect on the plaintiff's participation on July 29, 2010

3. Determination

A. The nature of the supplementary participation

In case where the plaintiff won the lawsuit, the plaintiff's supplementary intervenor becomes effective as a judgment revoking the disposition revoking the project implementation authorization pursuant to Article 29 (1) of the Administrative Litigation Act. Thus, although the plaintiff's supplementary intervenor stated Article 71 of the Civil Procedure Act when the plaintiff's supplementary intervenor applied for intervention, and the court of first instance also decided to allow the plaintiff's supplementary intervenor's supplementary intervenor's supplementary intervenor's supplementary intervenor's supplementary intervenor's supplementary participation, notwithstanding the name of the claim or legal ground and the decision of the court of first instance, it is reasonable to view the plaintiff's supplementary intervenor

B. Effect of withdrawal of a lawsuit without the consent of the Plaintiff’s Intervenor

(1) Article 67(1) of the Civil Procedure Act, which applies mutatis mutandis to the intervention in a co-litigation, provides that “any one of the co-litigants shall have an effect only for the benefit of all the co-litigants.” The meaning of the said provision is that any benefit in the litigation by either of the co-litigants is invalid for all of the co-litigants, and any disadvantage that may be inflicted on all of the co-litigants is null and void. Therefore, the same shall not apply where a party independently, without the consent

In full view of the points described below, it is reasonable to view that the plaintiff's supplementary intervenor who took the action on July 29, 2010 is an unfavorable litigation against the plaintiff's supplementary intervenor. The withdrawal of the lawsuit by the plaintiff alone without the consent of the plaintiff's supplementary intervenor is invalid. Therefore, the above argument by the plaintiff's supplementary intervenor is justified.

(1) In order to ensure the stability of procedures in legal relations of litigation, what procedural acts are beneficial to the parties, whether they are disadvantageous to them shall be determined uniformly by procedural acts according to the impact on the rights and positions of the parties under the Civil Procedure Act as of the time when procedural acts are performed, taking into account the nature of litigation procedures, the nature of the subject

② The Plaintiff’s Intervenor may independently act by participating in a lawsuit, and has the rights and status under the Civil Procedure Act, such as seeking a judgment on a subject matter of lawsuit, etc. The Plaintiff’s withdrawal of lawsuit loses the rights and status of the Plaintiff’s Intervenor. The loss of such rights and status that the Plaintiff’s Intervenor obtained as a result of the Plaintiff’s intervention would be disadvantageous to the Plaintiff’s Intervenor. The same applies to the Plaintiff’s Intervenor’s intervention that took place after the lapse of the period for filing the lawsuit, as long as the Plaintiff’s Intervenor is allowed to intervene regardless

③ The Plaintiff has the right to withdraw a lawsuit that has already been filed and the lawsuit has not been pending from the beginning, but such right may also be limited. In the case of a co-litigation intervention, the Plaintiff’s right to withdraw the lawsuit is limited in accordance with Articles 78 and 67(1) of the Civil Procedure Act to protect the interests of the Plaintiff’s Intervenor.

④ In light of the fact that an administrative litigation seeking revocation of an administrative disposition, such as the instant case, has a heavy effect as well as the limitation of the period for filing a lawsuit, the waiver of the claim taken place may substantially be the same result as the waiver of the claim taken place, there is a need to restrict the Plaintiff’s right to withdraw the lawsuit

4. Conclusion

Therefore, the judgment of the court of first instance that the lawsuit in this case was terminated on July 29, 2010 by the plaintiff's withdrawal of lawsuit is unfair, and thus, it is revoked, and the main text of Article 8 (2) of the Administrative Litigation Act and Article 418 of the Civil Procedure Act shall be applied mutatis mutandis, and the case shall be remanded to the Seoul Administrative Court which is the legal ground of the first instance.

Judges Gangnam-gu (Presiding Judge)