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

The grounds of appeal are examined.

1. Article 33(1) of the Trade Union and Labor Relations Adjustment Act provides that “The part of the rules of employment or labor contract that violates the criteria for the treatment of workers and other labor conditions as prescribed by the collective agreement shall be null and void.” Article 33(2) of the same Act provides that “The matters not prescribed by the labor contract or the part which is null and void under paragraph (1) of the same Article

Therefore, the normative part of the collective agreement is effective to directly regulate the labor contract relations between workers and their employer.

2. The reasoning of the lower judgment reveals the following facts.

On February 13, 2010, the Intervenor joining the Defendant (hereinafter referred to as the “ Intervenor”) concluded a probationary employment contract with the Plaintiff, and joined the Defendant as a probationary bus driver.

The rules of employment of the plaintiff provide that the new employee may be employed when it is recognized that his/her ability and character are appropriate for a period of on-the-job training for three months.

B. On May 3, 2010, the Intervenor entered into a labor contract with the Plaintiff from May 5, 2010 to January 30, 2011 during the training period.

On January 26, 2011, the Plaintiff notified the intervenors that the period stipulated in the labor contract is terminated on January 30, 201, and that the labor contract is terminated between the Plaintiff and the Intervenor.

C. On the other hand, on April 23, 2008, the Plaintiff entered into a collective agreement with Jeju Regional Headquarters General Trade Union (hereinafter “instant trade union”) by setting the term of validity from April 1, 2008 to March 31, 2010, and entered into the same collective agreement again on May 3, 2010. Article 18 Subparag. 2 of the collective agreement provides that “the company shall be classified as an intern worker or a suspended worker, and the internship and temporary worker shall have a three-month probation period.