This study aims to analyze the sports activities after school and phenomenon of specific student(s) being collectively shunted aside, and analyze the effect of sports activities on the phenomenon of being shunted aside by group, with a view to preventing specific students from being left out in the cold and emphasizing the importance of sports activities. The object of this study is 4 classes with different school grade composed of male students and female students at K middle school located at Gyeonggi-do, Questionnaire were distributed to a total of 12 classes, among which 504 returned them. Except the data from 32 persons who were not considered to have faithfully responded and the data which had some details left out, data collected from a total of 472 persons were used for this study. First, 195 middle school students(41.3%) responded that they have encountered a situation where they were shunted aside collectively or currently see around 1 person being shunted aside by group of students in a class. 179 middle school students(37.9%) answered that they also thought about their possibility of being shunted aside by group. In addition, 164 middle school students(34.7%) responded that they thought that the person who was shunted aside had the problem. Meanwhile, 211 middle school students(44.7%) said that they did not intervene when they saw a person was being shunted aside by group. Second, the analysis on the harmful effect that sports activities after school have on the collective shunting of specific student(s) indicated that the type of sports activities after school had a statistically significant difference in relation to the collective shunting at the level of p<.05. Third, the analysis on the degree of harmful effect that sports activities after school have on the collective shunting of specific student(s) indicated that there was a statistically significant difference at the level of p<.05 in relation to the degree of harmful effect on the collective shunting of specific student(s).