The main purpose of this study was to examine the effects of computer assisted self-supervision(CASS) on the improvement of teaching skill and teaching efficacy for beginning teachers, performed for 23 weeks. A brief summary of this study is as follows: First, CASS does improve teaching skill for beginning teachers. The result of the sub-hypothesis shows that CASS did increase Flander's major class verbal index and Tuckman's instructional atmosphere impressively. Secondly, the group that conducted CASS scored higher teaching efficacy than the group that performed the traditional instructional supervision. This study found the following results: First, CASS is a practical method of improving the teaching skill and efficacy of beginning teachers. It means that if they adopt CASS to improve the teaching skill and teaching efficacy, they could get satisfactory result. The result was possible, as CASS supported self-supervision of teachers by helping the environment of human resources and physical condition based on computer system. Second, self-supervision is based on scientific class analysis by computer system contributing to the improvement of instructional technology and instructional efficacy. The reason why CASS brought the improvement in teaching skill and efficacy can be referred back to the fact that it adopts the instructional analysis tool which was rarely approached in studies conducted from the past. In conclusion, supporting CASS with cyber supervision agents effectively reflects the instruction skill level of teachers and their requests. It provided customized service to teachers by appointing cyber supervision agents for teachers that follow self-supervision to meet instruction skill level of teachers and their requests. It is highly recommended to use CASS for improving the instruction expertise on campus for the beginning teachers. Plus, the needs are suggested for operating CASS centered by teaching skill and efficacy rather than the traditional one which conducts clinical supervision, collegial supervision, and administrative monitoring, as well as on-campus training. Also, to consider our education's reality constituted by the absence of the process to build up trusts between teachers and supervisors coupled with the hierarchy, CASS is definitely one of the realistic countermeasures. Especially, it is recommended that beginning teachers solve challenges step by step including problems in classroom CASS as well as acquire the complete package of teaching skill by launching a support system through cyber-supervision agents.