It is important for the elementary school children to produce the play rule for regulating theirrelationship. The rule productions of the elementary school children were observed in theirplay situation. Participants were from the first grade to the third grade children in elementaryschool. Observations were made 27 days for two months using a tape recorder and field notes.One-hundred sixty-six rule production episodes were collected and analyzed. The reasons ofproducing rules were categorized into 14 patterns. The main results showed that there weremany selfish reasons, the confirmation of the rule and the reasons by considering the humanrelations. And there were some reasons for the equity and the amusement. These resultssuggested that the elementary school children produced the selfish rules but could revised therules with the consideration about others.