Generally, in Japanese as a Second Language (JSL) teacher education, various teaching approaches are introduced to trainee teachers by highly experienced teachers or specialists. This training helps trainees acquire a particular body of knowledge about JSL, and hopefully through this approach, teaching methods that are commonly perceived to be correct will be taught and practiced. Recently, because the variety of Japanese language students has increased, there has been a growing need to consider students' needs and purposes of study in curriculum design. Consequently, teachers have had to develop and modify their teaching methods to suit these more diverse needs. The paper suggests that in order to promote prospective teachers' creativity and thinking skills, a new direction is needed for teacher development through critical reflection and collaboration. The author has been involved in Japanese language teacher education in a night course for adults. In the teaching methodology and practicum classes, trainee teachers have been gradually increasing their autonomy as individuals through opportunities for self-directed reflective practice and in collaboration with fellow trainees through post-practice mutual evaluations. This paper discusses this teacher training practice in relation to a reinterpretation of autonomy theory from learner autonomy toward teacher autonomy. (SM)