Many scholars and practitioners have acknowledged the importance of transformation leadership as a critical catalyst of creativity in an organization. But, current research on the association between TL and creativity has some limitations because they have mainly focused on the individual employee's creativity with a single mediator and a single-level analysis. As firms increasingly rely on teams' to enhance their innovation, however, we need to take into account factors that affect team-level creativity. To address this issue, we attempt to find underlying mechanisms which drive the relation between transformational leadership and team-level creativity. Grounded on a group creativity model, we argue that transformational leadership improves team creativity through employee's psychological safety and subsequently facilitating his or her individual-level creativity. To test the hypotheses, we conducted a multi-level structural equation modeling analysis by utilizing a survey of 196 employees of 52 teams in South Korea. The result shows that our hypotheses are supported. Theoretical and practical implications are discussed along with limitations and future research directions.