The process of identity formation and features of the ego in Western culture are different in Japan in which the maternal principle is predominant. In this paper Japanese Christian students, who believe in a culturally different religion, a paternal religion, are compared to non-Christian students as regards identity, ethics, commitment, and object relations. The results show that; 1) Japanese Christian students show more consistency between speech and action and are more tolerant of loneliness. But there is no significant difference with regard to identity or ethics. 2) The non-Christian parent group score lowest in field-based ethics and tend to score higher in identity and devotion (commitment). From this, it seems that for Japanese, the mode of belief in a religion is a more important factor for identity and ethics than the traditional features of the religion they follow.