A recording medium which carries a program to be used for executing whole or part of the first step of inputting as data (a) a unit environmental load of a constituent material constituting a product and (b) load ratio of an environmental load of a constituent material constituting a reference product to a total environmental load of the reference product, the second step of inputting information relating to a weight of a constituent material constituting an object product, and the calculation step of calculating a total environmental load of the object product based on the inputted data and the inputted information by way of a computer,
- wherein the calculation of the total environmental load of the object product based on the stored data and the inputted information consists of (a) a calculation of the total environmental load of the object product based on an environmental load of the constituent material constituting the object product, which is calculated based on the unit load to be applied on the environment of the constituent material constituting the object product and the information relating to the weight of constituent material constituting the object product, and the load ratio of the environmental load of the constituent material constituting the reference product to the total environmental load of the reference product or (b) a calculation of the total environmental load of the object product based on a converted load to be applied on the environment per unit number of the constituent material constituting the object product, which is calculated based on the unit load to be applied on the environment of the constituent material constituting the object product and the load ratio of the environmental load of the constituent material constituting the reference product to the total environmental load of the reference product, and the information relating to the weight of the constituent material constituting the object product.