The evolution of trade rules on agricultural products has three aspects: firstly, from intervening to market mechanism to ʻmarket-orientedʼ; secondly, from that mainly of "mass-production and mass-consumption" products to that of "small-scale production and small-scale consumption" products; and thirdly, elaborated in a more and more detailed manner in function of the purposes and characteristics of the measures in question. Due attention should be paid to the WTO's trade issues resolving functions and rules elaboration functions as well as regional trade agreements' tendency to ‘supplement' the WTO rules as well as to realize the difficult of achieving each country's interests in the WTO. Japan has to have a clear self-recognition of the ʻqualityʼ merits of its products and make the best use of the trade rules.