A new CAI system, which would support the students developing their creativities so as to enhance the awareness of the issues, the ability to dig into new research subjects, and be equipped with the problem-solving powers, has been designed and developed. The salient feature of this CAI system is that it is used for group learning by which each learner can develop the ability to advance his thought through the mutual discussion. Moreover, in order for the students to prevent from scattering away the study course and to facilitate them with effective learning, a personified agent is used as a cooperative associate which would assist learners with the natural communication with the personified agent, by using voice conversation function in Japanese natural language. The subject experiments conducted to evaluate the new CAI system, resulted in that this CAI system would be effective in developing the fundamental ability of learners to tackle a posed new issue, and to think about deeply.