The purpose of this paper is to clarify what kind of factors affect team errors through the case of manufacturing class in Tokai polytechnic college. Based on recovering theory of team errors, three factors are found; human relationship, technical knowledge, and diffu sion of responsibility. First, human relationship factor affects first step in team making process because they don’t understand mutually. Second, technical knowledge factor affects middle step because they lack of knowledge and certain evidence for pointi ng out of errors. Third, diffusion of responsibility factor affects manufacturing step because they’re inexperienced of manufacturing in fact. Especially, third factor is distinctive feature in students. In educating manufacturing knowledge and skills, the se factors are considered and educators are needed to be conscious for nurturing teamwork.
