The purpose of this study is to analyze the effects of unstructured and spontaeous role-playing in pro-social behavior of a child. The experimental group in this study is 7 children who go to after-school class in J. social welfare facility and the controlled group is 7 children in composition class., While the experimental group did role-playing with each other the control group did not have any treatment, In order to find out effects of an experiment pre-test first post-test and second post-test were done. The results can be concluded as following. First in pre-test the degree of behavior resulted the same in experimental group and in controlled group. However in the first post-test the pro-social behavior of the experimental group with role-playing showed an improve than that of the controlled group. Therefore it can be emphasized once more that the role-playing improves pro-social behavior of a child. Second in the second post-test done 2 moth after the role-playing it was found that the pro-social behavior of experimental group keep the improved points as in the first post-test Therefore it can be concluded that the effect of role-playing on pro-social behavior of a child is continuous.