[2] Whether the proviso of Article 141 of the Civil Act, which limits liability of an incompetent person, applies mutatis mutandis to cases where a juristic act becomes null and void due to a lack of capacity (affirmative), and the burden of proving the existence of benefit (=person lacking capacity)

[3] The case holding that in a case where a person without will to have a right to collateral security established on a real estate owned by him and borrowed money from a financial institution to a third party, the financial institution is entitled to seek the transfer of the above claim, which is an existing interest, even if it is not possible to seek the return of the loan itself, since the profit from the loan exists in the form of a loan claim or a claim for return of unjust enrichment against the third

[2] The proviso of Article 141 of the Civil Act that limits the liability of an incompetent person is a special provision under Article 748 of the Civil Act that sets the scope of return of the beneficiary in unjust gains, and its purport is to limit the scope of return to the existing interests without asking about the good faith and bad faith for the protection of the incompetent person. Thus, even in a case where a juristic act becomes null and void due to a defect in the capacity of opinion, it shall be applied mutatis mutandis. However, in a case where a person gains profits from another person's property or labor without any legal cause and thereby causes damage to another person, if such acquisition is a pecuniary gain, such money shall be presumed to exist regardless of whether the person who acquired it consumed it. Thus, the claimant who did not have the above interest, namely, bears the burden of proving

[3] In a case where a person without mental capacity set up a collateral security on the real estate owned by himself and borrow money from a financial institution and lends the money to a third party, the case holding that the financial institution can seek the transfer of the above claim, which is an existing interest, even if it is not possible to seek the return of the loan itself, since the profit from the loan exists in the form of a loan claim or a claim for return of unjust enrichment against the third party

1. The judgment of the court below

In full view of the adopted evidence, the court below concluded a loan transaction agreement of this case with a loan of KRW 50 million from the defendant on November 20, 2003, and completed the registration of creation of a neighboring mortgage in the name of the defendant association with a maximum debt amount of KRW 65 million against the real estate owned by the plaintiff to secure this agreement. At the time of the loan of this case, the non-party 1, the plaintiff, together with the plaintiff, signed the loan transaction agreement of this case and the mortgage contract of this case on behalf of the plaintiff, signed on behalf of the plaintiff and used the above loan amount of KRW 50 million for the business fund of the non-party 2, who was his own children. The plaintiff paid monthly interest on the above loan of this case for one year. Meanwhile, the plaintiff suffered from an unidentified disease due to unknown causes in the first grade of elementary school in around 1962, resulting in verbal and mental disorder to the elementary school, and was able to have his family's life at the middle age of 60 through 74 years old, and recognized the plaintiff's social ability to communicate.

Based on the above facts, the court below affirmed the conclusion of the judgment of the court of first instance which accepted the plaintiff's claim by rejecting all the defenses by the defendant union that the plaintiff should return the above loan transaction agreement of this case to the defendant union as unjust enrichment, even if the loan transaction agreement of this case was null and void, and the loan transaction agreement of this case and mortgage contract of this case between the plaintiff and the defendant union should be null and void since they were made in the state of lack of mental capacity. Accordingly, the court below affirmed the loan transaction agreement of this case by paying part of the principal and interest of this case and confirmed the loan of this case, etc. of this case, or even if the loan transaction agreement of this case is null and void, the plaintiff must return the above loan of 50 million won to the defendant union as unjust enrichment at the same time as the cancellation of the registration of creation of mortgage of this case.

2. Ground of appeal No. 1

The mental capacity means mental ability or intelligence that can reasonably determine its meaning or result based on normal perception and towing ability, and the existence or absence of mental capacity should be determined individually in relation to specific juristic acts (see Supreme Court Decision 2001Da10113, Oct. 11, 2002). In particular, in a case where a certain juristic act is granted with a special legal meaning or effect that is difficult to understand only the ordinary meaning, it needs to be understood not only as a day-to-day meaning of the act, but also as a legal meaning or effect (see Supreme Court Decision 2006Da29358, Sept. 22, 2006).

Examining the evidence admitted by the court below in light of the records, the fact-finding and judgment of the court below on the plaintiff's capacity to act as the plaintiff is just and acceptable, and there is no violation of the rules of evidence or misapprehension of legal principles as otherwise alleged in the ground of appeal.

3. The second ground for appeal

The court below rejected the defense of ratification of the loan transaction agreement of this case on the ground that it is not sufficient to recognize that the plaintiff ratified the loan transaction agreement of this case with the knowledge that the loan transaction agreement of this case was null and void, and there is no other evidence to acknowledge it. In light of the records, the court below's findings of fact and judgment of this part can be deemed legitimate and there is no other error of law such as violation of the rules of evidence, misapprehension of legal principles, omission of judgment, etc.

4. Ground of appeal No. 3

With respect to the simultaneous performance defense of the defendant union, the court below rejected the defense on the ground that there is no evidence to support the plaintiff that there is a benefit from the loan transaction agreement of this case, and rather, it is recognized that the non-party 1 received the loan of this case and used it as a business fund of the plaintiff. It is difficult to accept the decision of the court below on this ground.

Article 141 of the Civil Act provides that "a cancelled juristic act shall be deemed null and void from the beginning. However, an incompetent person shall be responsible for redemption to the extent that there exists any benefit arising from the act." The proviso of the above Article which limits liability of an incompetent person is a special rule of Article 748 of the Civil Act which provides for the scope of return of the beneficiary in unjust enrichment, and its purpose is to limit the scope of return to the existing interest without asking for the good faith and bad faith for the protection of the incompetent person. Thus, even where a juristic act becomes null and void due to a defect in the capacity of opinion, it shall be applied mutatis mutandis. However, where a juristic act takes advantage of another person's property or labor without any legal cause and inflicts loss on another person, if the acquisition is a pecuniary benefit, the money shall be presumed to exist regardless of whether the person who acquired it has consumed it (see Supreme Court Decision 96Da3281 delivered on December 10, 196). Thus, the above person who asserts it and the incompetent person shall bear the burden of proof.

According to the facts and records acknowledged by the court below, since the loan of this case 50 million won was received by the non-party 1 and used for all the business funds of the non-party 2, and the non-party 2 was delivered as the borrower and the non-party 1 as a joint guarantor to the plaintiff, it seems difficult for the plaintiff to pay the principal and interest properly. However, it is difficult for the plaintiff to pay the loan without considering the possibility of recovery, etc., the loan itself has already been consumed since it was no different from the waste of money. However, since the loan of this case and the non-party 1 and the non-party 2 had the loan claim or the return claim for unjust enrichment (the above loan is likely to be invalidated due to the plaintiff's office ability, it appears that the loan of this case remains in the form of the above claim. Thus, even if the defendant union cannot seek the refund of the above loan itself as invalid due to the loan transaction agreement of this case, it can be viewed that the plaintiff's obligation to simultaneously cancel the loan of this case can be viewed as the duty of fair and good faith.

Therefore, the court below's decision to reject the simultaneous performance defense of the plaintiff is erroneous by failing to exhaust all necessary deliberations as to the existence of profits or by misapprehending legal principles, which affected the conclusion of the judgment, and thus, the appeal by the defendant association pointing this out is justified.

5. Conclusion

Therefore, among the judgment below, the part of the claim for cancellation of the registration of establishment of a mortgage is reversed, and that part of the case is remanded to the court below for a new trial and determination. It is so decided as per Disposition by the assent of all participating Justices.

Justices Park Ill-sook (Presiding Justice)