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

The defendant shall pay to the plaintiff KRW 2,573,60 and to the plaintiff on June 1, 2017.

1. The parties' assertion

A. The Plaintiff is obligated to pay the Plaintiff the remainder of 4.7 million won for the construction cost (the remainder after deducting one million won for the Plaintiff’s 5.7 million won for the construction cost) and the damages for delay, given that the Plaintiff subcontracted the construction work for 4 households of multi-household housing located in Seongbuk-gu, Seongbuk-gu, by determining the construction cost as KRW 5.7 million from the end of April 2017 to the end of May 2017, and completed the construction from the end of May 2017.

B. The Plaintiff and the Defendant concluded a subcontract by designating the construction cost as one million won, and the Defendant paid all the above construction cost on May 1, 2017, so there is no remainder of the construction cost that the Defendant shall pay to the Plaintiff.

2. Determination

A. The following facts can be acknowledged by adding up the whole purport of the pleadings to the statements in Gap evidence No. 2 and Eul evidence No. 6, and the entry in Gap evidence No. 5-1 shall not interfere with the above recognition:

1) On February 2017, the Defendant is the Seongbuk-gu Seoul Metropolitan Government Ground D Building E, F, G, and H (hereinafter “instant building”).

A) The Plaintiff was awarded a contract for the extension of the building. On April 2017, the Plaintiff is a telecommunications work for the instant building from the Defendant (hereinafter “instant construction”).

2) The Plaintiff received a verbal subcontract (hereinafter “instant contract”).

(2) At this time, the Plaintiff and the Defendant did not separately determine the construction cost. (2) The Plaintiff completed the instant construction work from the end of April 2017 to the end of May 2017.

B. According to the above facts and the purport of the argument, it is reasonable to deem that the Plaintiff agreed to settle the construction cost on the basis of the expenses actually incurred with the Defendant (On the other hand, in the construction contract, it does not necessarily have to set the specific construction cost in advance, but it includes a considerable amount of profit in accordance with the transactional practice for the actual expenses.