The purpose of this study was to analyze the mediating effect of pedagogical content knowledge of science teaching on the relations among child care teachers’ burnout, science teaching anxiety, and science teaching efficacy. For this study, questionnaires were distributed to 355 teachers working at child care centers in Jollanam‐do. The analysis of data was conducted with SPSS WIN 18.0. The results of this study were as follows. First, child care teachers’ burnout lowered their science teaching efficacy, and child care teachers’ pedagogical content knowledge, as a mediating variable, reduced the negative effect of child care teachers’ burnout on their science teaching efficacy. Second, child care teachers’ science teaching anxiety lowered their science teaching efficacy, and child care teachers’ pedagogical content knowledge, as a mediating variable, reduced the negative effect of child care teachers’ science teaching anxiety as an independent variable on their science teaching efficacy. These findings imply there is a need to boost pedagogical content knowledge during in-service teacher education programs.