Abstract: The purpose of this study is to investigate the effects of teacher-training program for computing education using theme-based approach through co-teaching on computing teaching self-efficacy of pre-service kindergarten teachers. Computing teacher training program for young children requires cooperation of preschooler specialist and computer specialist, so, cooperative pedagogy can be the most appropriate method for it. The program using theme-based approach is suitable for teaching computational thinking in integrated classroom environments for preschoolers. If teacher-training program is structured using theme-based approach through collaborative teaching, it will have a positive effect on pre-service kindergarten teacher’s computing teaching efficacy belief. Therefore, in this study, we designed the computing teachers training program based on theme approach through collaborative teaching and applied it to pre-service teachers who are going to work for the program after kindergarten. As a result, personal computing teaching efficacy belief of pre-service teachers showed a significant difference at the significant level 0.05. In addition, we conducted individual interviews on co-teaching strategy and subject-based approaches. Through these in-depth interviews, we confirmed that the teachers had positive effects by verifying the benefits of the teachers training programs for computing education using theme-based approach through collaborative teaching. The computing teachers training program using theme-based approach through collaborative teaching method can be one of the realistic alternative for the on-the-job training of the pre-service kindergarten teachers.