The purpose of the present study was to clarify changing patterns in children’s behavioral traits before and after entering school. The Strengths and Difficulties Questionnaire （SDQ） was conducted to quantify the behavioral traits of children before and after entering school. The SDQ Scores data of 118 children were analyzed. Non-hierarchical cluster analysis revealed that the children should be categorized into 7 clusters. The characteristics of the each cluster were discussed in terms of SDQ Scores and the characteristics of children included in the each cluster. This suggests that each cluster is different from the others. And then, the meaning of patterns which were identified on the basis of the SDQ Scores was discussed in terms of the following issues. （1）Identified patterns could be helpful to clarify children’s behavioral traits that reflect individual differences before and after entering school. （2）Identified patterns could be helpful for childcare worker to predictively understand children’s behavioral traits and to take care of children based on such understanding.