Degination, which is the requirement for fraud, refers to all affirmative or passive acts that have to observe each other in the wide sense of trust and good faith in the transaction of property, and it does not necessarily have to be an essential part of a juristic act, and it is sufficient if it is based on the basis of judgment that an actor wants to dispose of property by omitting the other party in mistake.

(See Supreme Court Decision 2009Do7459 Decided October 15, 2009, etc.). In a case of exercising a right by means of deception, if the exercise of a right by means of deception is to the extent that such deception cannot be acceptable as a means of exercise of a right by social norms, the act of exercise of a right constitutes fraud.

In a case where the contractor or subcontractor agrees to pay the construction price in installments in accordance with the ratio of the completed payment calculated by the contract or subcontract of a construction project, if the contractor or subcontractor claims for the completed payment by withdrawing the construction volume and the amount of the construction work to be paid in installments, and if it is deemed that the act of receiving such payment has breached the duty of trust and good faith in the transactional relationship, and thus, has reached the extent that it is not acceptable as a means of exercise of the right under the social norms, it can be recognized as fraud.

At this time, whether such an act is permissible under social norms should be determined by comprehensively considering the difference between the design quantity and the construction quantity, the quantity difference, the cause and method of calculating the ratio, the method of determining the contract price and the possibility of adjusting the contract price according to design change.

The court below, including the price-fixing method recognized by the employment evidence, is the contents of the subcontract concluded by P Co., Ltd and AD Co., Ltd., and it is a material that does not collapse in tunnels by fixing it to be fixed to be bet and bet.