Objective. Recently, the CO₂ emission of organization such as Scope 3 has been disclosed by many companies in Japan, partly because they have to report it to the rating organization such as CDP. In this context, the company that provide products（material, parts, etc）and service have to disclose the CO₂ emission of their products and/or service to their customers. As Sun Messe Co., Ltd. Japan is a printing company, the CO₂ emission was caused mainly by used paper and energy consumption for printing, which should be allocated to customers. In this paper the difference of the results by allocation methods were introduced.

Results and Discussion. The total amount of the CO₂ emissions of Sun Messe Co., Ltd. was 78,736 t-CO₂ in 2012, which was allocated by the following three allocation methods. Case 0 was based on the sales, which was introduced as the most popular method in the guidance of Scope 3. Case 1, Case 2 and Case 3 were based on the product quantity, the cost of printing paper and the weight of printing paper respectively. As the examples of the customers, three companies were selected. The main products of company A, B and C are flyers for sales promotion, books, and direct mails, respectively. The allocation results by three cases were completely different. However, if the CO₂ emissions should be allocated by the physical background, the allocation method based on the weight of printing paper might be recommended.

Conclusions. In the guidance of Scope 3, the allocation method based on the sales is popular, but the characteristics of the works of the company should be reflected. Moreover, it should be agreed with the customer.