In 1949, a teacher certification law was established, and teacher education began in Japanese colleges and universities. National, public and private four-year colleges and universities, and junior colleges have supplied secondary school teachers, whereas national colleges of teacher education have been a key provider of teachers of elementary schools in which homeroom teachers teach all subjects. Types of teacher education institutions and the functions have been diversified: private colleges of education, child education and human development have begun supplying many elementary school teachers, and professional schools of teacher education have been established for pre-service and in-service education at the graduate level. The quality of new teachers has been maintained through a highly competitive “open system” of teacher employment which mandates passing examinations. As teachers are government officials, their status is guaranteed. Various opportunities for professional development are provided to educators. In addition, large staff rooms where all teachers gather to engage in school-wide practical and cooperative research may contribute to the improvement of teacher’s skills and expertise, foster teamwork among teachers, and positively impact school administration.