This study aims to clarify what factors made and transformed ‘teaching style’ in physical education of Junior High School Teacher B through interpreting a life history of Teacher B. The results are summarized as following points. 1. The ‘teaching style’ of Teacher B on physical education in the I period (1989.4-1997.3) was made by factors of ‘belief as a teacher’ and ‘reflection on his teaching based on chances of professional development and resources left by predecessor and books’. 2. The ‘teaching style’ of Teacher B in the III period (2005.4-2017.3) was transformed by factors of ‘meeting with Mr. E and Mr. F belonging to C Attached Junior High School Q’ and ‘learning of the theory of physical education’.