A system for evaluating an environmental impact during a life cycle of an activity includes a controlling unit, which controls the system with a plurality of data storage elements connected to the controlling unit. The plurality of data storage elements includes a first data storage element, a second data storage element, a third data storage element, and a fourth data storage element. The first data storage element stores a first data type for each item to be used for the activity as life cycle inventory data. The second data storage element stores a second data type for each item, which includes grade information and recycle ratio information. The third data storage element stores a third data type for each item as modified life cycle inventory data. The third data type is obtained by modifying the first data type with the second data type. The fourth data storage element stores impact-coefficient data for each item.