The costs of appeal are assessed against the defendant.

1. Whether the plaintiffs' participation in the strike of this case constitutes grounds for disciplinary action of this case

(a) If an industrial action by a worker is deemed legitimate, all of the following conditions must be satisfied:

First, the subject should be the subject of collective bargaining.

Second, the purpose should be to promote autonomous negotiations between labor and management in order to improve working conditions.

Third, when an employer refuses to conduct collective bargaining with regard to specific demands for improving the working conditions of workers, it shall be commenced, and unless there are special circumstances, it shall undergo the procedures prescribed by the law, such as the approval decision

Fourth, the means and methods should not be consistent with the user's property rights, nor fall under the use of violence.

(See Supreme Court Decision 2004Du10852 Decided April 29, 2005, etc.). Here, the purpose of this context is to create autonomous negotiations between labor and management for the purpose of improving working conditions means that the requirements to be achieved by the dispute can be collective bargaining matters.

(1) In a case where an industrial action is conducted on September 30, 1994 (see, e.g., Supreme Court Decision 94Da4042, Sept. 30, 1994). In a case where a part of them is not justifiable, the propriety of the purpose of the industrial action shall be determined pursuant to the legitimacy of the main or genuine purpose. In a case where an industrial action is deemed not to have been conducted if it was excluded from an unreasonable

(See Supreme Court Decision 2007Du12859 Decided June 23, 2009, etc.). B.

The court below held that the strike of this case in which the plaintiffs participated constitutes legitimate industrial action in terms of its subject, purpose, time, procedure, means and method.