A. On March 2014, the Plaintiff offered a bid to newly construct a specialized breeding machine (hereinafter “instant construction”) on the Gyeong-si, Kimcheon-si (hereinafter “instant construction”), and the Defendant was selected as a successful bidder in the said bid.

Then, while entering into a contract for the instant construction project, the Plaintiff and the Defendant: (a) concluded a contract for the instant construction; (b) on the same amount as the original contract amount, the Defendant, a specialized facility company in the Yang-ro Construction Industry (hereinafter “ Sungjin Construction”), both performed the instant construction project; and (c) on the condition that the Defendant is in charge of the relevant management work.

B. On March 14, 2014, the Plaintiff and the Defendant concluded a construction contract with the owner of the instant construction work in KRW 5,479,00,000,000, and subsequently reduced the construction cost under the said contract at KRW 5,000,000 on November 30, 2014.

(hereinafter “instant construction contract”). On April 23, 2014, the Defendant entered into a construction contract that subcontracts the instant construction project to KRW 5,663,00,000,000, in total, the price for the instant construction. On November 30, 2014, the said contract was reduced to KRW 5,000,000 as the price for the instant construction contract, and the instant construction project completed the construction project in entirety.

C. On March 25, 2014, the Plaintiff paid KRW 821,850,00 to the Defendant under the pretext of advance payment. The Defendant paid KRW 298,802,077 out of the above advance payment as advance payment, and the remainder KRW 523,047,923 (==821,850,000 - 298,802,077) was not paid as advance payment or construction cost.

[Ground of Recognition] A without dispute, Gap evidence 1 through 3, 5, 7, 11, Gap evidence 4, 6-1 through 3, Gap evidence 8-1 through 12, Gap evidence 9-1 through 9, Gap evidence 10-1 through 8, Gap evidence 14-1, 2, Eul evidence 1 through 6, Gap witness's testimony, whole purport of pleading

2. The plaintiff and the defendant concluded the construction contract of this case as stated above.