1. Of the judgment of the court of first instance, the part against the defendant exceeding the amount ordered to be paid below shall be revoked.

1. Facts of recognition;

A. On November 2013, the Plaintiff contracted a contract for the extension of the C University Students' Center located in Yongsan-gu Seoul Metropolitan Government (hereinafter “instant construction”), and subcontracted the sewage pipeline construction among the instant construction to the Hoho Development Co., Ltd. (hereinafter “Sho Development”).

B. From November 7, 2013, the Defendant engaged in the business of leasing construction machinery with the trade name of “D” requested the Plaintiff and Hoho Development to lease the construction equipment necessary for the instant construction work at the said construction site. The Defendant leased the equipment at the said construction site; and the equipment rental fee of KRW 2,464,00 (including value-added tax; hereinafter the same shall apply) was paid on December 30, 2013 by the Plaintiff.

(The Plaintiff and the Defendant issued a tax invoice of KRW 3,102,00 on November 30, 2013, but reduced KRW 638,00 on December 30, 2013, thereby filing a tax invoice of KRW 2,464,00.

On March 18, 2014, the Plaintiff received a request from the Central Construction, a central construction, which is another construction machinery rental company for the instant construction project, to pay KRW 3,740,000. The Plaintiff’s employee wired KRW 3,740,000 to the Defendant’s national bank account account due to mistake on April 18, 2014.

[Ground of recognition] Unsatisfy, Gap evidence Nos. 1-5, 7-9 (including virtual number), the purport of the whole pleadings

2. Determination on the cause of the claim

A. According to the above facts, the defendant was found to have obtained unjust enrichment by receiving KRW 3,740,000 from the plaintiff on April 18, 2014 due to the transfer of error by the plaintiff's employee, without any legal cause. The defendant argued to the effect that the defendant had the equipment cost of KRW 4,741,00 which was paid from Hoho Development, and the plaintiff did not erroneously transfer the money directly to the defendant for such settlement because there was the payment for the work cost unpaid to Hoho Development Co., Ltd., and the payment was not paid to the defendant for that settlement. However, the time when the plaintiff directly transferred the money directly to the defendant and the time when the error remittance was made.