Unconscious thought, defined as a situation where conscious attention is directed elsewhere rather than on the decision being made, has been reported as an effective way to uncover a target's lie (Reinhard et al., 2013). We reexamined the study of Reinhard et al. in a Japanese setting and also investigated how perceivers' personality traits related to accurate lie detections and true/false response tendency. Moreover, we examined how lie detection affected perceivers' interpersonal relationships. An experiment was conducted with 56 university students. Results indicate that students were more likely to make correct judgements when targets told the truth than when they lied. However, unconscious thought did not increase lie detection rates or true/false response tendency compared with conscious thought and control conditions. Among the personality traits that we used, state anxiety, social skills, and tendency to lie affected the lie detection rate. State anxiety also affected the true/false response tendency. Finally, perceiving a target telling the truth led participants to want to continue relationships, and this process was mediated by the impression of the targets. The cultural differences in unconscious thought, possible reasons our results did not replicate the findings of Reinhard et al., and the importance of state anxiety in lie detection are discussed.