1. The third acquisitor who acquired the ownership of the mortgaged real estate from the mortgagee who is the owner of the mortgaged real estate in order to secure another person's obligation shall be in the position similar to the mortgaged real estate in that the third acquisitor who acquired the ownership of the mortgaged real estate shall lose the ownership of the mortgaged real estate upon the exercise of the mortgage. Therefore, the provisions of Articles 370 and 341 of the Civil Act on the right to indemnity of the mortgagee shall apply mutatis mutandis to the third acquisitor who acquired the mortgaged real estate from the mortgagee's property in accordance with the provisions on the right to indemnity, unless there are special circumstances where the third acquisitor who acquired the mortgaged real estate by the mortgagee's property has repaid his obligation or has lost the ownership of the mortgaged real estate due to the exercise of the mortgage (see Supreme Court Decision 97Da8403, Jul. 25, 1997).

2. According to the evidence duly admitted by the court below, ① EPS Korea Co., Ltd. (hereinafter “EPS”) entered into a loan agreement with the Defendant on May 25, 200 with a loan of KRW 4.5 billion, and entered into a factoring transaction agreement with the loan of KRW 4.6 billion on March 28, 2001 (hereinafter “each of the above loan agreements”); Nonparty 1, the representative director of EPS, guaranteed EP’s debt with respect to each of the instant loan agreements; ② Nonparty 1 entered into a comprehensive mortgage agreement with the Defendant on June 9, 199; ② the registration of establishment of a mortgage on the instant real estate with the debtor EP and the maximum debt amount as KRW 200 million was completed on the following grounds: ③ the real estate was sold on March 28, 2001 to Nonparty 37, which was subject to the ownership transfer registration on March 13, 201, and the ownership transfer registration on the instant real estate was made on March 27, 2001.

Examining these facts in light of the legal principles as seen earlier, Nonparty 3, who acquired and owned the instant real estate on the ground of donation, lost ownership due to the enforcement of the right to collateral security, has the right to claim reimbursement against EP. against the debtor. Nonparty 1, who was the founder of the right to collateral security, cannot be deemed to have the right to claim reimbursement against EP.

Although the reasoning of the judgment below is inappropriate at the time of establishing the reasoning, the plaintiff's claim in this case based on the premise that the non-party 1 is entitled to the right of reimbursement against EP, that is, the right to reimbursement arising from the execution of the above collateral security right, pursuant to the subrogation clause, was transferred to the non-party 1, the obligee's claim against EP and the right to collateral. Since the defendant extinguished his right to collateral by collecting the right to collateral and disposing of it voluntarily, the defendant is obligated to return 200 million won to the non-party 1 as unjust enrichment. The plaintiff is the transferee of the above claim for return of unjust enrichment from the non-party 1, and the plaintiff rejected the claim for return of unjust enrichment against the defendant. In conclusion, there is no error of law by misunderstanding the legal principles on

3. Therefore, the appeal is dismissed, and the costs of appeal are assessed against the losing party. It is so decided as per Disposition by the assent of all participating Justices on the bench.

Justices Lee In-bok (Presiding Justice)