The purpose of this paper is two-fold: first, to reexamine concepts of “practical-teaching-skill” spread out widely through the country: and second, to show the importance of study of university-based teacher educators in Japanese context. In Japan, teacher educators who are formerly involved in teaching at primary or secondary schools in long period of time, i.e. “teacher educators with teaching experience at school,” are expected to make student-teachers nurture “practical-teaching-skill.” Practical-teaching-skill is evaluated as an important competence for a long time, but recently is getting paid special attention in Japan. The definition of this competence, however, is ambiguous and it has been used as a telling phrase. We examined the usage and understanding of this word and criticized the naïve understanding which were spread among teaching universities, and student-teachers. Then, we introduced and showed the significance of the studies of teacher educators which were recently proceeded in the US. After that, we focused on “reflection,” which was assumed as important for professional growth of teacher educators, and reexamined this concept for developing student-teachers’ practical-teaching-skill.