1. The plaintiff's appeal is dismissed.

2. The costs of appeal shall be borne by the Plaintiff.

The purport of the claim and appeal is the purport of the appeal.

The reasoning of the judgment of this court citing the judgment of the court of first instance is as follows, except where the following is added to the judgment on the claim for cancellation of contract based on the Plaintiff’s mistake, and thus, it is consistent with the main sentence of Article 420 of the Civil Procedure Act.

In addition, the defendant asserts that even if there are errors, the contract cannot be revoked because there is gross negligence on the part of the plaintiff.

In a case where there exists an error in a material part of the contents of a juristic act, such declaration of intention may be revoked, but such error may not be revoked if it was caused by gross negligence of the

(Article 109(1) of the Civil Act. However, according to the overall purport of Gap 2, Eul 4’s statements or images, and witness D’s testimony and pleading, the plaintiff confirmed the site at the time of the instant sales contract and explained that there was an extended part in the balcony of the instant real estate, and that enforcement fines may be imposed thereon, it can be acknowledged that such content is specified as a special contract.

In such a case, if the purchaser of real estate is the purchaser of the balcony, he/she has a duty of care to properly ascertain whether there is a defect in the violation of the Building Act in the area of balcony expansion, or to at least to identify the exact meaning of the "performance penalty" as stipulated in the special agreement in the sales contract, and if he/she paid little attention, he/she could easily be aware

Therefore, even if the Plaintiff concluded a sales contract by mistake that there was no violation of the Building Act on the instant real estate, it should be deemed that there was gross negligence on the part of the Plaintiff.

Ultimately, the plaintiff's assertion of cancellation of contract on the ground of mistake cannot be accepted in this reason.

The plaintiff's claim for conclusion shall be dismissed as there is no reasonable ground.

The judgment of the court of first instance is the same.