The purpose of this study was to explored the roles and competencies of leaders in professional learning communities(PLCs), that is, the characteristics of successfully conducted PLCs and experiences of leader. Participants in this study were four leaders who were working in different PLCs, two were from PLCs at elementary and middle school each and two were from the out of school PLCs in local and national wide each. In order to collect data, various materials were gathered such as artifacts, video clips, and observations & interviews from the preparation, progression and post process of the workshop. The main analysis data were artifacts and videos. We focused on analyzing the collected data repeatedly and answering questions about the role and capacity of the leader. As a result, roles of leaders in PLCs could be grouped into tasks, assistants, facilitators, and messengers. The strengths of leadership were passion, flexibility to listen and reflect on others' opinions, and attitude of dedication. The difficulty in running PLCs was the difficulty, burden, and lack of time of spontaneous driving. In order to overcome this problem, the PLCs needed to improve the system and build a cooperative and communal nature. In the case of out-of-school PLCs, we found that they were leaning on individual leader's passions. Through those successful leaders' talks and reports, we were able to find the role and capacity of leader as follows; initiative, communication, determination, vision presentation, enthusiasm, professionalism, and respect.