This study examines the effects of supervisors' positive feedback (PF) and negative feedback (NF)frequencies on their subordinates, focusing on the mediating effects of trust in the supervisors. A surveystudy was conducted with 475 employees from 4 companies responding as subordinates. Results fromanalyses based on structural equation modeling showed that (1) PF frequencies were positively related tothe subordinates' evaluation of their supervisors' three components of trustworthiness: ability, integrity,and benevolence, whereas NF frequencies were only related to trustworthiness in ability; (2)subordinates' evaluations for the three components of trustworthiness were all related to trust in theirsupervisors and, in turn, trust was related to the affective component of organizational commitment andjob satisfaction regarding their own growth. These results elucidate the findings of previous studies,explaining why and how the effect of PF on subordinates is stronger than that of NF, and that even NF,which may threaten the self-image of subordinates, has positive effects.