The objective of this study was to propose motivation for the analysis of consumer’s purchasing behavior and willingness to pay for the new soymilk products in cooperative stores. We surveyed the purchasing behavior, willingness to purchase, willingness to pay, and impact factors on willingness to pay. The results indicated that most consumers drank soymilk more than once per week. The reasons for consuming soymilk were health, nutrition, and taste, in order. When purchasing soymilk, consumers considered environment-friendly, quality, country of origin, brand, and price, consecutively. Taste was also an essential quality factor. Thus, consumers showed some willingness to purchase new soymilk products. In addition, cooperative members considered environmental characteristics of raw material and improvement of preference for final product as more important than functionality or food additives. Differentiation of process and marketing strategies are required for the development of soymilk products for cooperative members.