© 2019 Authors. This paper proposes a pacing system that makes dialog robots mimic the pacing technique in order to promote trust relationships between humans and robots. Pacing is a communicative technique that synchronizes breathing or how to speak with a person to build relationships among humans. The experiment was performed by comparing the impression of human subjects' conversation with a robot when the pacing system was applied or not applied. The evaluation used both subjective and objective perspectives. From the subjective perspective, the results show significant differences for the questionnaire items concerning "feeling friendliness," "feeling fun," "feeling an emotional connection," "feeling synchrony," "motivation to use" and "listening to the user" between the with and without pacing conditions. Also, from the objective perspective, there is a significant difference in sympathetic activity in heart rate variability.