This study examined the mediating role of psychological safety in the relationship between leader-member exchange (LMX) quality and members' proactive behavior and voice behavior. Through a review of prior studies, the relationships among LMX quality, members' proactive behavior and voice behavior, and psychological safety were examined, and based on these theoretical discussions, a research model and hypotheses were formulated. Data from a total of 213 dyads (426 individuals) collected from 32 companies that had adopted a team-based organizational structure were used in the final empirical analysis. The results showed that LMX quality had a significant positive effect on members' psychological safety, and members' psychological safety had a significant positive effect on their proactive behavior and voice behavior within the organization. It was also confirmed that LMX quality exerted a significant indirect effect on proactive behavior and voice behavior through psychological safety. On the other hand, LMX quality did not have a significant direct effect on members' proactive behavior, but had a significant negative direct effect on voice behavior. Through these findings, this study confirmed that LMX quality influences members' psychological safety, which in turn has a positive sequential effect on the enhancement of proactive behavior and voice behavior.