The purpose of the study was to investigate perception of prospective teachers' about education for international understanding. Research questions are set up as follows; Frist of all, what are the level of prospective teachers' concerns and understanding of education for international understanding? And its differences between elementary school prospective teachers and secondary school prospective teachers are significant? Secondly, what do they have opinions about curriculum development and class offering of education for international understanding? Lastly, what do they think about reasonable objectives, contents, and teaching skills in curriculum development of education for international understanding? To figure out the answers of the research questions, the study employed mixed method by using both a survey and a focus group interview. 431 prospective students from national universities of education and the teacher colleges took part in the study. Twenty seven participants were placed in each five focus group. In findings, prospective teachers' concerns about education for international understanding were low. The levels of understanding about the themes of education for international understanding was lower than concerns. Even though there were significant differences between elementary and secondary prospective teachers in the level of concerns and understanding, meaningful differences were not appeared. They were more interested in environmental matter, starvation, and multi-cultural teaching. Prospective teachers preferred class offering of education for international understanding in a sophomore year with two credit hours. They did not agree with the need of a subject of education for international understanding because of burden from teacher employment exam. The researchers suggested that it was necessary to re-conceptionalization of a teacher certificated course. Developing contents for critical thinking and field-study were additionally provided as alternatives in the study.