The aim of this paper is to clarify the factor of qualitative differences in the social studies teaching plans designed by the pre-service teachers. In this study, we investigated by the two following ways. First, we required student to design the teaching plan as assignment of "Teaching Social Studies" class, and compared the plans. Second, we conducted the interview for them to hear the background of their plans. As a result, the factors of the differentia among them are as follows. (1) It depends on whether they had experienced the high-quality Social Studies class from their elementary to high school. (2) It depends on whether they have the will to examine and apply the newly-acquired theories thought in the university critically. These results suggest that to encourage the student to reflect on their own perceptions on the meanings of learning/teaching Social Studies is significant for the pre-service teacher.