This study aims to investigate the structures active in human resources development of subordinates by supervisors, and the effect of situational factors on individual supervisor behaviour. Respondents were 250 supervisors working for various Japanese organizations. Several behavioural traits, which had not been identified in previous research, were addressed. Situational factors include: (1) employee development-linked appraisal systems and, (2) the influence of career interviews given by supervisors on the human resources development of subordinates. Individual supervisor factors include: (1) interest in careers, (2) commitment to the task and, (3) the influence of feeling threatened by a high performing subordinate on the human resources development of that subordinate. Additionally, differences amongst personnel at the management level were found with respect to supervisor behaviour and influencing factors.