Multiple trade unions in a business unit are enforcing on the 1st of January, 2010, hereby, according to Trade Union & Industrial Relations Mediation Act(hereinafter referred to as "TUIRMA") Addenda Article 5(3), the government has continuously gone through the unification of the bargaining channel to start the multiple trade unions. In businesses, however, in case of multiple trade unions permitted, not solely can the problem of the unification of the bargaining channel be brought up. Namely, in case of multiple trade unions permitted, the member of the full-time officer of a trade union, the problem of Union-shop, the adaptation of collective bargaining agreement(hereinafter referred to as "CBA"), unfair labor practices in discriminations between unions, etc, are expected to be occurred, like this, under the multiple trade unions, various actions, their unfair labor practices and other side effects could be a point at issue. So, this study went through the problems of convenience service, industrial actions, check-off among the problems under the multiple trade unions or the unification of the bargaining channel, as the follows are; First, the judgment of yes or no discrimination among unions should be depend on the existence of the duty of employer`s neutral intention and the reasonable discriminative reason made by employers, in field of the employer`s convenience service. Union office and Union`s bulletin board) under the multiple trade unions. Second, in case of being forced to unify of the bargaining channel under multiple trade unions, according to analogy interpretation of TUIRMA, it is desirable for only union which won the approval of majority in the concerned business or the member of all unions in business to take industrial actions. This is why it is desirable for the entire bargaining union members as the subject of industrial actions to take steps because the legally binding of CBA could affect all union members in concerned business. Third, in case of all multiple trade unions permitted in concerned business, it is more likely to be brought a legal act on the check-off. So, in labor law, a political examination must be necessary, including whether the regulation on the check-off should make obvious or leave it to the regulation interpretation on the unfair labor practices, TUIRA Article 81.