While teaching practice in school for pre-service teachers currently gains more attention by researchers who find positive effects for mentors, it has not been focused yet how teaching practice instruction could be the arena of professional development for school-based teacher educators. To discuss the importance of fostering professional development of school-based teacher educators through teaching practice in school, this paper held an interview with four teacher educators who experienced growth through teaching practice instruction. Through the analysis of their narratives of how they view teaching practice instruction, experience-based learning process to be a teacher educator was found with four key categories. This paper then reconstructed experiential learning model: Those key categories played important roles for proceeding experiential learning cycle that indicates strategies for the professional development.