The purpose of the study is to investigate the mediating role of job satisfaction in the relationship between teacher aptitude and teacher-infant interaction. Data was collected in September 2020 from childcare teachers working at childcare centers in the city of Hwaseong through snowball sampling, and 224 questionnaires were used for the analysis. Descriptive statistics, correlations analysis, and mediation analysis were conducted using SPSS 23.0. The results shows that there were significant correlations among the three key variables, namely teacher aptitude of childcare teachers, job satisfaction, and teacher-infant interaction. The mediation analysis confirmed a significant mediating role of job satisfaction in the relationship between teacher aptitude of childcare teachers and teacher-infant interaction, and partial mediation was found. Implications and suggestions for future research were discussed.