1. The Defendant shall pay to the Plaintiff KRW 41,00,000 and the interest rate of KRW 15% per annum from October 12, 2017 to the date of full payment.

1. Facts of recognition;

A. On May 4, 2017, the Plaintiff: (a) determined to install air conditioners for the third to seventh floors among the buildings scheduled to open the Dvalescent Hospital in the Busan-gu, Busan-gu (hereinafter “instant building”); (b) the construction cost shall be KRW 18 million (including value-added tax); and (c) the construction cost shall be KRW 30 million at the time of work on May 8, 2017; (d) the intermediate payment amounting to 60% prior to the delivery of the product; and (e) the remainder amount equivalent to 10% after the installation and operation; and (e) concluded the instant contract by determining the date of completion as the date on which the permit for the establishment of a medical institution is issued (hereinafter “instant contract”).

B. At the time of the contract, the Plaintiff decided to install a secondhand product with respect to the installation of air conditioners on the second floor among the Defendant and the building, separately setting the construction cost of KRW 9 million.

C. On May 8, 2017, the Plaintiff remitted each of the Defendant a down payment of KRW 30 million, and the intermediate payment of KRW 20 million on July 20, 2017.

On September 7, 2017, the defendant completed the construction of the second floor among the buildings, but the construction of the third floor to the seventh floor was discontinued at the site.

E. On September 8, 2017, the Plaintiff obtained a license to establish a medical institution in the D/L hospital from the head of Busan District Office.

F. On the other hand, on September 11, 2017, the Plaintiff concluded a contract to install air conditioners in the system with G and trading price of KRW 110,00,000 (including value-added tax) that had been engaged in air conditioners installation business with the trade name “F” in Busan-gu, Busan-gu.

[Ground of recognition] Unsatisfy, entry of Gap evidence 1 to 4, purport of whole pleadings

2. The assertion and judgment

A. According to the above facts finding as to the cause of claim, the Defendant is obligated to pay the Plaintiff the total construction cost of KRW 50 million, which was paid to the Plaintiff as unjust enrichment, less KRW 9 million for the second floor of the building, the total construction cost of KRW 41 million, and delay damages therefrom.

B. The defendant's assertion