The purpose of this study was to clarify the process of the change in interaction between a child and nature through a child's involvement with others. Nature is regarded as important in early childhood education and care, and the educational effects of nature are clarified in some earlier research. However, this earlier research focused on the importance of nature, or some of children's abilities fostered as a result of their involvement with nature, and this previous research did not clarified the process of each child's change. Therefore, in this study, we selected a child at a specific kindergarten, and researched the process of how he changed as a result of his interactions with nature. We observed the actions of the child in nature by video fieldwork and selected some episodes in which he was absorbed in activities with nature. Next, we analyzed the data using the Steps for Coding and Theorization (SCAT) method. The result of this study is summarized in the following two points: 1) the child's initial interest in and involvement with others, and 2) the child's behavior changed when interacting with nature. In the first point, we noted the change in the child's interest. At first he was interested in his teacher and in the other children, but he gradually grew more interested in nature. In the second point, the child's behavior changed when interacting with nature. At first, his behavior was passive, but it gradually, became positive. These changes were a result of his concern with contents of activities in nature.