A. On December 24, 2018, the Plaintiff entered into a construction subcontract with the Defendant (hereinafter “instant contract”) with the content that the Defendant would accept installation works for automatic control devices (including value-added tax), among the remodeling works for the F Hospital located in Ansan-gu E-gu, Ansan-si, which was contracted by the educational foundation D, by setting the construction cost of KRW 40,520,00 (including value-added tax) and the period from December 21, 2018 to December 29, 2018.

The details of the instant contract concerning the payment of the price are as follows.

6. Payment of the price;

(a) Advance payment: No one; and

(b) Partial amount paid for completion: 100% in cash.

(1) Adjustment and payment (2) within 30 days from the date the person placing an order receives an adjustment in accordance with the contents and proportion of the adjustment (2) within seven days from the date the person placing an order receives an adjustment from the person placing an order;

B. The Plaintiff completed the construction under the instant contract, and around February 2019, prepared a modified contract with the Defendant to change the contract amount to KRW 38,500,000 (including value-added tax) and drafted a settlement agreement with the said amount to the contract amount.

C. On May 24, 2019, the Plaintiff sent a content-certified mail demanding payment of KRW 38,500,000 to the Defendant, which was served on the Defendant on May 27, 2019.

[Ground of recognition] Facts without dispute, entry of Gap evidence 1, 2, and 5 (including branch numbers, if any) and the purport of the whole pleadings

2. Determination

A. According to the above facts of recognition as to the cause of the claim, barring any special circumstance, the Defendant calculated the Plaintiff at a rate of 38,500,000 won per annum under the Commercial Act from May 28, 2019 to August 29, 2019, the delivery date of the original copy of the instant payment order, from May 24, 2019, and 12% per annum under the Act on Special Cases Concerning the Promotion, etc. of Legal Proceedings from the next day to the date of full payment.