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 National Armed Forces Administration under the Defendant’s control publicly announced the instant bid for the manufacture and installation of the D Hospital UPS storage cell by means of limited competition among small and medium enterprises on the B date. The Plaintiff, who is engaged in the manufacture and sales business of information and communications equipment, and the storage cell manufacturing business, participated in the said bidding and was determined as the successful bidder on July 17, 2015.

B. Accordingly, the Plaintiff and the Defendant concluded a contract for the manufacture and installation of D Hospital UPS storage batteries (hereinafter “instant contract”) on August 5, 2015, setting the contract amount of KRW 171,167,640 as well as the delivery date from August 5, 2015 to October 5, 2015.

C. On August 5, 2015, the Plaintiff entered into a guarantee insurance contract with the Seoul Guarantee Insurance Co., Ltd. (hereinafter “Seoul Guarantee Insurance Co., Ltd.”) with respect to the instant contract from August 5, 2015 to October 5, 2015, setting the insured amount as KRW 17,116,764 (hereinafter “instant guarantee insurance contract”), and submitted the guaranty insurance policy issued to the Defendant from the Seoul Guarantee Insurance Co., Ltd. on the same day.

On August 12, 2015, the Defendant paid KRW 51,000,000 to the Plaintiff under the name of advance payment pursuant to the instant contract.

E. After that, the Plaintiff did not supply the storage batteries to the Defendant by October 5, 2015, and the Defendant notified the Plaintiff of the rescission of the instant contract on October 22, 2015 on the grounds that he/she failed to perform his/her duty to supply storage batteries.

F. On November 3, 2015, the Defendant claimed the Plaintiff to return the said advance payment of KRW 51,000,000,000, and the Plaintiff refused to comply therewith, and on November 9, 2015, the Defendant filed a claim against the Seoul Guarantee Insurance for payment of KRW 17,116,764 based on the instant guarantee insurance contract.

[Ground of recognition] Facts without dispute, Gap evidence Nos. 1, 3, 4, 6, Eul evidence Nos. 1 and 2, the purport of the whole pleadings

2. Judgment on the main defense of this case

A. Of the instant lawsuit, the guaranteed insurance is the gist of the Defendant’s assertion.