1. The judgment of the court of first instance is modified as follows.

The defendant shall pay to the plaintiff KRW 317,752,461 as well as to the plaintiff on April 2016.

1. Basic facts

A. On April 2015, the Plaintiff entered into a joint supply and demand agreement with the Defendant, under which the members of the joint supply and demand organization, the Defendant as joint supply and demand organization, and the Defendant’s joint supply and demand agreement under which the Gyeonggi-do Government Office of Education (hereinafter “instant construction”) orders the Defendant to jointly supply and demand new construction works ordered by the Gyeonggi-do Government Office of Education (hereinafter “project owner”).

B. On April 30, 2015, the Plaintiff and the Defendant jointly contracted the instant construction work from the ordering person to KRW 724,283,030, the construction period from May 6, 2015 to January 30, 2016, Plaintiff 49, and Defendant 51%, respectively.

After that, the construction cost of the instant project was KRW 749,930,000, and the construction period was changed on February 29, 2016.

C. The instant construction was completed on February 29, 2016.

On September 25, 2015, the ordering person paid 113,35,530 won (231,297,000 won x 49/100) to the Plaintiff as the first payment for the completion of the instant construction project on September 25, 2015; and paid 117,961,470 won (231,297,000 x 51/100) to the Defendant; and on April 29, 2016, paid 232,772,540 won (475,06,000 x 49/100 x 49/100) to the Plaintiff; and paid 242,273,460 won (475,046,000 x 510/100) to the Defendant respectively.

[Ground of recognition] Facts without dispute, Gap evidence Nos. 3 through 5, 8, 9, 11, 17, Eul evidence Nos. 12 and 13 (including each number; hereinafter the same shall apply), the purport of the whole pleadings

2. The parties' assertion

A. The Plaintiff and the Defendant entered into a joint supply and demand agreement with respect to the instant construction project. Since the Plaintiff actually performed all the construction works, the settlement of the construction cost ought to be made according to the actual contribution ratio.

Therefore, the Defendant’s portion corresponding to the Defendant’s share of 51% out of the instant construction works (hereinafter “the Defendant’s share portion”) against the ordering person regarding the Plaintiff who performed construction works beyond its share ratio.