1. The part of the instant lawsuit regarding the claim to nullify the invalidity of the construction contract is dismissed.

2. The plaintiff's remaining claims are dismissed.

1. Facts of recognition;

A. On June 23, 2016, between the Plaintiff and the Defendant’s Form C, representing the Defendant, concluded a construction contract with the Defendant to install urban gas-using facilities up to the housing located in Jung-gu Daejeon, Daejeon, the Plaintiff-owned (hereinafter “instant construction contract,” and the said contract “instant construction contract”).

The main contents of the instant construction contract are as follows.

내용 금액 비고 공사비 250만 원 부가가치세 별도(10%) 계약금 중도금 배관공사 착공 시 잔금 250만 원 가스통입 시 완불 ◆ 공사금액내용(도시가스 사용시설 공사금액 견적서) ◆ 별도 시설 분담금, 인입공사 분담금, 수용가 분담금(도시가스사 청구 시 은행납부) 가스렌지 연결비 분배기 교체비 보일러 이설비 사도 공사비는 거리 측정 후 별도 지불함(1m당 20만 원)

B. On November 7, 2017, the Plaintiff paid the construction price of KRW 2.5 million to the Defendant.

C. On April 18, 2018, the Plaintiff notified the Defendant that “The instant construction contract was concluded with a non-authorized agent C and thus null and void.”

[Ground of recognition] Facts without dispute, Gap evidence Nos. 1, 3, and 6, the purport of the whole pleadings

2. The gist of the Plaintiff’s assertion was known to the Defendant, and the Plaintiff concluded the instant construction contract, but revoked the said contract on the ground that it was an unauthorized agent before the Defendant ratified it.

In addition, according to Article 18-3 of the Urban Gas Business Act, the defendant, other than general urban gas business operators, could not install and construct urban gas pipelines (in-house pipelines) on the plaintiff's housing, belongs to the plaintiff and concluded the construction contract

In addition, the construction of this case is attached Table 7-1 of the Enforcement Rule of the Urban Gas Business Act when reclaiming urban gas pipelines underground.

There is a serious defect that has not been installed safety devices to block gas supply as prescribed in the provisions of this paragraph.

Therefore, since the instant construction contract is null and void, it is against the defendant.