This study reports on the effects of preparation activities of ice breaking and pre-debate for debate in intermediate intensive Japanese class. The process of ice breaking involved self introduction, interviewing each others and reporting to class about the interview. Not only were the students able to express their opinions freely, but they also able to form the foundations for debate which are "listening to and understanding others" and "speaking plainly to the audience". Pre-debate makes students notice the importance of respect for others' opinions, cooperation in the group, and using suitable ways to express their opinions.