We examined whether Japanese dating couples have cynical intuitions about how their partners assess responsibility and whether the strength of this "naive cynicism" varies with the intimacy of the relationship. Thirty-eight undergraduates and their dating partners rated their own responsibility for six desirable and six undesirable joint activities and predicted their partner's self-ratings. They expected their partners to overestimate responsibility for desirable activities and underestimate responsibility for undesirable activities. In addition, this tendency was at least a result of their expectation that their partner's allocation of responsibility would be motivationally biased. Although partners in a more intimate relationship appeared to expect their partner's allocation of responsibility to be more biased, whether this tendency was found because of an assumption that their partner was more biased or because of the stronger self-effacing tendency of more intimate partners was not clear. Results were discussed in terms of judgmental bias in self versus others.