This study is to compare the EU with Japan from the sides of environment and energy in order to recognize the importance of Renewable Energy Sources (RES) and to find out the supply policy of RES. Since municipal waste and manure is increasing rapidly, RES like biomass could solve the problem of environmental contamination. The EU took the policy of Feed in Tariff (FIT) at the beginning stage of RES supply, concluding that FIT is more effective policy than Renewable Portfolio Standard (RPS). The experiences of the EU and Japan indicate that market should be formulated to succeed the policy of RES.