1. All of the plaintiffs' claims are dismissed.

2. The costs of lawsuit are assessed against the plaintiffs.

1. Facts of recognition;

A. The apartment sales contract between the plaintiffs and the defendant 1) No. 303 (hereinafter referred to as "the apartment of this case") is executed.

On January 29, 2014, the registration of ownership preservation was completed in the future of the Defendant on January 29, 2014. 2) On October 14, 2014, the Plaintiffs concluded a sales contract to purchase the instant apartment from the Defendant for KRW 170 million (hereinafter “instant sales contract”).

B. The Plaintiffs paid the purchase price and the transfer registration of ownership are fully paid to the Defendant the purchase price of KRW 170 million and completed the registration of ownership transfer on October 27, 2014 with respect to each of 1/2 shares of the instant apartment.

[Ground of recognition] Facts without dispute, entry of Gap evidence 1 to 3, purport of the whole pleadings

2. The plaintiffs' assertion and the defendant concluded a sales contract with the purchase price of KRW 170 million on the premise that the area of the apartment of this case is 35 square meters. Thus, the sales contract of this case constitutes the sale that designated the quantity.

However, the actual area of the apartment of this case was limited to 95.526 square meters and approximately 29 square meters, which are the sum of sections for exclusive use (76.071 square meters) and sections for common use (19.456 square meters).

따라서 피고는 원고들에게 이 사건 매매계약에서 약정한 면적에서 실제 면적을 공제한 부분의 매매대금에 해당하는 29,142,852원[= 1평당 4,857,142원(≒ 1억 7,000만 원 ÷ 35평) × 6평(35평 - 29평)]을 반환할 의무가 있다.

3. Determination

A. 1) In the instant sales contract’s entry, the size of the instant apartment is indicated as approximately 35 square meters in the size column of the instant sales contract. (2) The instant apartment is indicated as the size of the section for exclusive use and the size of 19.456 square meters in the collective building ledger of the instant apartment. (B) At the time of the conclusion of the instant sales contract, the instant apartment was extended to the size of the balcony 22.6943 square meters.