The judgment below is reversed and the case is remanded to Seoul High Court.

The grounds of appeal are examined.

1. The lower court determined that the Plaintiffs’ claim for the payment of additional statutory allowances and retirement allowances based on the calculation of hourly ordinary wages including continuous service allowances, work allowances, work allowances (hereinafter “work-based allowances, etc.”) and bonuses is unreasonable in light of the concept of justice and equity, since it is considerably difficult to manage the Defendant’s unexpected financial burden, or the company’s existence is at risk, it cannot be accepted as it violates the principle of trust and good faith.

2. Judgment of the Supreme Court

A. The principle of trust and good faith (hereinafter “the principle of trust and good faith”) refers to an abstract norm that a party to a legal relationship should not exercise a right or perform a duty in a manner that violates equity or trust in consideration of the other party’s interest. In order to deny the exercise of the right on the ground that it violates the principle of trust and good faith, it should have been given to the other party or objectively deemed that the other party has a good faith. The exercise of the right against the other party’s good faith should have come to the extent that it is not acceptable in light of the concept of justice.

If the contents of the labor-management agreement, such as a collective agreement, are null and void in violation of the Labor Standards Act’s compulsory provisions, the assertion of invalidation is an exercise of rights contrary to the good faith principle, and if it is rejected on the ground that it is an exercise of rights contrary to the good faith principle, it would be a result to discomp

However, the contents of the labor-management agreement are mandatory provisions of the Labor Standards Act.