In order for the agricultural co-operatives to survive, it is necessary to reconsider the factor of “predominance” and to make adequate use of it. Therefore, this paper aims to theoretically consider the predominance of business developments which agricultural co-operatives can use to demonstrate in their competition with companies. In approaching the task, the predominance of the agricultural co-operative business currently is considered, based on conventional theoretical development regarding predominance. Firstly, the Masuda paper, which conducted an accurate review of the theories on predominance of agricultural co-operatives on business development, in addition, presented some questions to the theories is examined. Secondly, the Kamegai paper and Shibagaki paper, focusing on the comprehensiveness of the agricultural co-operative business, are reviewed. Thirdly, based on the above reviews, as for the current predominance of agricultural co-operative business, the problem is considered in terms of both predominance in common to business and that of each business. As a result, the current predominance of the business needs to incorporate the predominance by the sense of attribution of members, comprehensive business system, co-creation of values with members and co-operatives social responsibility, to consider scope economies and ripple effects in addition to scale economies and organizational strength effects. In addition, not only the predominance common to business but also that of each business should be considered.