This study focused on the difficulties that elementary school teachers experienced in science classes and the self-efficacy in science teaching through narrative inquiry. For this purpose, a research participant was selected in a 10-year career teacher who is a typical elementary school teacher who took none-science track in high school and majored none-science subject in the university of education, but who currently has a high level of self-efficacy in science teaching. I shared the participant’s experiences related to science and science lessons and analyzed the meaning of the experiences according to four stages: before entering the university of education, at the university of education, at the beginning of teaching in elementary school, and after entering the graduate school. It also revealed that the accumulation of educational experience, understanding the nature of science education, encounter and communication, and extension of external relations and challenges influenced elementary school teacher to improve self-efficacy in science teaching. Based on this, some implications for education were suggested.