In order to remove the excessive nutrient salt at Port of Amagasaki, we have established the method to utilize the cycle of life: by cultivating seaweed at the port, removing shellfish from the upright sea walls, and turning them into compost. In cooperation with the local junior high school students, local citizens, experts, and administration, the junior high schools of Amagasaki provided the environmental study through this activity, based on the theme of “Cycle of Life”. In this report, we describe about the effects of this study. 1) Before the study, a survey showed that most of the students had bad impression toward Amagasaki Sea, such as “dirty” and “smelly”. However, after the study, the impression turned into better impression such as “fun” and “more familiar”. 2) In the Technology class, the students successfully cultivated more than 50 kinds of vegetation. As the students cooked and ate the vegetables and fruits they grew, the study also developed into “Food Education”-learning the connection between their health, environment, and food. 3) The students cooked using the oil extracted from the seeds of rape blossoms cultivated with their compost. Then they watched waste oil being refined and turned into bio diesel fuel, which activated car engine. Through such experiences, many students realized the cycle of life as “the life continues in different forms”, and the respect for life as well as developing their awareness to improve the natural environment.