Abstract
In these days, the customer needs for the product are more and more diversified. The company decides a concept satisfying these customer needs and performs development of products after having clarified functions to satisfy them. The customer does judgment whether the first satisfies one's demand for the product. And, there is a possibility of holding the expectation at the same time for the product that satisfies one's demand. The new demand and function caused by this expectation revolts original product demand and the function, and might obstruct the concept finally. Because the discussion about the customer's product expectation is insufficient in an existing product development process, in the present study, by using mathematical model, the authors proposed a product development decision model with added potential product expectation of the customer.
