The expression "children of concern" is often used among kindergarten teachers and nursery school staffs, however, there is no unified view or consensus regarding the meaning of this word and the area covered by this term. This study reviewed articles dealing with nursery school teacher's awareness of “children of concern”. Nursery school teachers tended to focus on an adaptive behavior which allow children to participate in group activities in the classroom, and also focused on social relationships such as eye contact and friend relationships. Clumsiness was also taken up as an important sign of the needs for special support. Furthermore, present study outlined various assessments for preschoolers. New assessment tool for nursery school teachers was developed with the aim of providing the basis of optimal support to meet the needs of each child. It is important to provide ongoing and transitional supports with a long-term prospect,and to prevent psychiatric comorbidities by sharing information among supporters based on objective evaluation from early development at nursery school.