Today, labor unions have become more serious and have more critical roles in the IT industry. Labor union should enhance the quality of working life in an organization. It is the most important role of the union to satisfy employees. When a labor union enriches its roles, members have a positive attitude to the union. Hence, workers will be more satisfied and make more positive results. Moreover, although members have positive attitudes to the union, when labor and capital have a negative relationship, workers do not make the best performance. Furthermore, although unions and the companies work in close cooperation, when members have a negative attitude to the labor union, workers’ performance will also decline. Hence, a positive attitude to labor unions and union-management relations has a mutual benefit for performance. This study explains these relationships with the effect of attitudes to labor unions (satisfaction, trust, and commitment) on organizational commitment and organizational citizenship behavior, and the moderate effect of union- management cooperation. The purpose of this study is to suggest that labor unions should have a positive relationship with management and win members’ recognition in the IT field.