Teacher training for elementary school foreign language education has been conducted since the announcement of the Course of Study for elementary schools in2017. There are basically two forms of teacher training : Off the Job Training(Off-JT)and On the Job Training (OJT). Off-JT can provide training to many teachers, but it is difficult to provide training based on the current situation and needs of each school. OJT can focus on a particular issue in the area or school, but the number of teachers who receive training is small. This paper presents a process and implementation of OJT focusing on lesson planning and assessment for elementary school foreign language education.