This study investigated the characteristics of family structures in various situations represented by Japanese university students. Subjects were required to express the typical structures of their past and the present families, and the ideal structures of their families in the future using Family System Test (FAST). The classification revealed that cases classified into the 'balanced' were not so many in both the past and the present family representations although some changes were found in the hierarchy and cohesion with the growth of the children. In contrast, the majority of the ideal future representations were classified into the 'balanced'. This means that many Japanese students, just as the researchers in Western countries, assume that the ideal structures of their own families should be highly cohesive and must have some generational boundaries. In addition, other analyses showed the differences in the characteristics between the past, the present and the future family structures.