The purpose of this study is to take a general overview of the research concerning the adjustment at the shift period from preschool childcare, such as kindergartens and day-care centers, to elementary school in Japan, and to examine orientation of the research and the problems. As a result of this study, the following aspects were clarified, 1) It is necessary to take not only the kindergarten transition, but also day-care center and the preschool transition. 2) It is necessary to limit the transition period from immediately before graduating kindergarten or preschool to just before entering first grade of elementary school. 3) According to the crisis theory of environmental transition, it is necessary to take into account the 3 important groups at the transition period, the children, the teachers (kindergarten teachers and nursery teachers teaching the senior graders, and elementary school teachers teaching the first graders), and the parents. 4) It is necessary to focus on the socio-cultural factors creating the atmosphere, that influences the adjustment and image of the child, in kindergarten, day-care center, elementary school, and family education. 5) It is necessary to make more longitudinal studies and practical research to understand children's adjustment process. Finally, this research suggests that it is necessary to take a systematic examination of the independent variables-kindergarten teachers, nursery teachers, elementary school teachers and parents, dependent variables- socio- cultural- environment factors.