This study aims to clarify the process of sharing and evaluating subtle massage comfort in the massage-chair development. As a result, the designers acquire sensory criteria while accumulating experience through new product development cycles. They evaluate massage action by the prototype function based on their experimental criteria. And many massage techniques are realized as the state of components or digital codes and are shared within the development department. By combining them, new massage functions are multiply created. At the final stage, the development manager evaluates the prototype massage function and totally optimizes to enhance the comfort of the product. From this case, it is clarified that this massage function development is the process which involves both manipulating the realized part and evaluating the massage action based on the shared experimental criteria.