The present article aims to give the theoretical and practical foundation for the "teacher development" curriculum which is subdivided into three. Historically, Teacher Training in the fifties and sixties emphasized the acquisition of linguistic knowledge, language habits and skills, or linguistic competence. Teacher Education in the seventies put stress on communicative proficiency and interactive skills, or communicative and interactive competence. Teacher Development in the eighties to the present has tried to harmonize them and integrate them into humanism in Japanese language education. Teacher Development is essential for the actualization and success of Holistic Approach.