1. The plaintiff's appeal is dismissed.

2. The costs of appeal shall be borne by the Plaintiff.

The purport of the claim and appeal is the purport of the appeal.

1. Basic facts

A. The Plaintiff is a person who awarded a contract for the construction of a dormitory expansion facility (hereinafter “instant construction”) to Sungdong Construction Co., Ltd. (hereinafter “ Sungdong Construction”), and the Defendant is a person who guaranteed the obligation to return advance payment to the Plaintiff of Sungdong Construction.

B. On June 23, 2016, the Plaintiff concluded each of the instant construction contracts (hereinafter “instant construction contract”) with an advance payment of KRW 1,335,659,50, and the construction period from July 1, 2016 to December 27, 2016.

C. On June 23, 2016, Sungdong Construction entered into a guarantee agreement with the Defendant for advance payment (hereinafter “instant guarantee agreement”) with a view to guaranteeing the Plaintiff’s performance of the obligation to return advance payment on the same day. From July 22, 2016 to March 27, 2017, Sungdong Construction paid KRW 390,00,000 as advance payment to Sungdong Construction on August 2, 2016.

Article 1 (Guarantee Liability) Construction Mutual Aid Association (hereinafter referred to as the "Association") of the Terms and Conditions of Advance Guarantee (hereinafter referred to as the "Guarantee") fails to pay the contractor (hereinafter referred to as the "debtor") the obligation related to the contract entered in the Guarantee Document to the other party (hereinafter referred to as the "Guarantee Claim") (hereinafter referred to as the "Guarantee Claim") due to the failure to pay the other party (hereinafter referred to as the "Guarantee Claim") within the Guarantee Period.

Article 2 (Grounds for Failure to Fulfill Guaranteed Obligations) Partnership shall not pay a security deposit in any of the following cases:

2. Where a guarantee accident occurs due to a cause for which the guarantee creditor is responsible;

D. Of the terms and conditions of advance payment guarantee incorporated into the terms and conditions of the instant guarantee agreement (hereinafter “instant terms and conditions”).