The purpose of this study is to clarify environment and assistance to enable children to play cooperating with others focusing on activities of five-year-old children working with a common aim. The method is recording environmental components and assistance adopted to encourage children to play cooperating with others when they did what they wanted to do and did sequence activities, and writing them down as practical cases. Then, we discussed these cases by childcare conferences held in our kindergarten and reflections by the teachers themselves. We examined and clarified whether those environmental components and assistance were appropriate. As a result, environmental components and assistance were clarified in the following four points: 1. interactions generating ideas which include others' feelings, 2. interactions which help children become aware of others' circumstances and work with them again, 3. interactions which encourage students to enjoy and get fulfillment about work with role sharing, 4. setting situations where children can listen to what others working together feel and think.