Abstract
The purpose of this study is to consider meanings of a participatory observer's existence to children in nursery school through analyzing an impressive episode from the author's experiences there. The analysis first shows that a participatory observer appears before children not just as a person observing them but as a concrete person who gives them a possibility of building up an intersubjective relationship. Secondly it deals with the finding that it is not until an observer has developed an actual relationship of "the self" and "the other" with children that we can truly understand the child's subjective world. These considerations suggest that the participatory observation is the method that urges an observer to respond to practical matters in the nursery school setting.