The on-site training for high-school students in the Takehara Marine Science Station of Hiroshima University roused their interest in the sea. Especially, generation experiment of sea urchin, anatomy of fishes, and animal collection in uninhabited island were the most popular among students. As a result of this training, understanding and the interest in almost all student's marine organisms and environments have increased, indicating that the on-site training might be effective in the prevention of high school student's losing interest in science.