Two studies examined relationships between general trust and improved mental health. Japanese university students participated in Studies 1 (n=325) and 2 (n=402) and they completed self-report measures assessing general trust, committed relationships, tendencies to make acquaintances, which is considered an aspect of extraversion, and negative affect. Consistent with the emancipation theory of trust, both studies indicated that general trust was negatively associated with committed relationships and positively associated with tendencies to make acquaintances. General trust was negatively associated with negative affect and neuroticism, and positively associated with proneness for experiencing positive emotions, which suggested an association between general trust and improved mental health. Study 2 indicated that tendencies to make acquaintances mediated the association between increased general trust and decreased negative affect. These findings suggest that general trust enables people to broaden their interpersonal relationships in daily life, and that the increase in available social support improve mental health. It is suggested that the emancipation theory of trust could be the basis for developing a model that explains mental health.