The purpose of this study is to reveal structures of environment and assistance in which five-year-old children play planning through trial and errors focusing on the most preferred "artistic play activities", with materials and tools around them. The methods of investigation are recording and writing down the circumstances in which five-year-old children do artistic play activities with materials and tools around them and structures of environment and assistance done by teachers as practical examples. Whether the environmental structure and assistance in these examples were appropriate or not was investigated by the teachers' conference and discussing these examples. As we accumulated practices, we found three points: 1. how to speak to children so that they could recall previous ideas and create new ones; 2. environmental structures planned how to show materials in order to make their ideas wider; 3. teachers' demonstrations of models so that children become curious of feelings of ''they want to try'' as environmental help for children playing planning through trial and error.