Believing biased information often causes conflicts between communities and prevents peaceful solutions of problems. Whaling (including dolphin hunting) is a topic that has caused serious differences of opinions. We conducted a peace education program with the whaling problem in a liberal arts education class for undergraduate students at Hiroshima University. In the class, the students viewed two documentary films of dolphin hunting practices in Japan, “THE COVE” and “Kujira to Ikiru (Life with Whale).” THE COVE stands on the side of anti-whaling and emphasizes the cruelty of dolphin hunting, whereas Kujira to Ikiru focuses on the fishermen’s life disturbed by anti-whaling groups. After viewing the films, the students answered a questionnaire survey regarding their opinion on whaling. Before viewing the films, the proportion of those who answered “agree,” “against,” and “neither” to whaling activity was 20%, 13%, and 67%, respectively. The proportion changed to 9%, 61%, and 30%, respectively, immediately after viewing THE COVE, and to 32%, 20%, and 48%, respectively after viewing Kujira to Ikiru . This suggests that the contents of the films strongly affected students’ opinions. Their comments suggest that they had realized the risk of trusting biased information and importance of knowing both sides of conflicting opinions. The results indicate that this peace education program is effective in learning the base of constructive and peaceful discussion on a problem.