This study was conducted to reveal the commonality between mother-child and romantic dyads in early adults, based on the relationships between early adult attachment dimensions, emotional experiences in the relationships, and evaluation of the relationships. Participants were 209 pairs of early adults and their mothers, and 103 romantic couples in early adulthood. The main results were as follows: in both relationships, attachment anxiety was positively correlated to one's own and one's partner's negative emotion in the relationship and negatively related to one's own and one's partner's evaluation of relationships. But attachment avoidance was only related to one's own negative and positive emotion in those relationships. Moreover, the relations between attachment anxiety and one's own and one's partner's evaluation of relationships were mediated by one's own and one's partner's negative emotion respectively in both relationships. The results were discussed in terms of the self-fulfilling prophecy of attachment styles.