In this study, we examined the relationships among higher brain function, trust or distrust, and gullibility in middle-aged and elderly people. It has been pointed out that the trust can be regarded the psychological frame of automatic processing in decision-making. The participants were 309 rural community dwellers (127 males and 182 females) whose mean age was 64.9 years old (SD = 9.9). The trust scale of Amagai (1997) and the Nagoya University Cognitive Assessment Battery were used to measure sense of trust and higher brain function, respectively. Gullibility was measured by self-report using two items. Correlation analyses showed that higher brain function positively correlated with degree of trust in others and negatively correlated with distrust. However, regression analysis demonstrated that only the relationship between category fluency and distrust was significant. Furthermore, the degree of distrust positively correlated with gullibility.