In recent years, the development of AI field is remarkable. In particular, it is remembrance that Alpha Go beat the world champion of Go. In 2019, the practical use of AI in the business area is advanced and what AI can solve or not will be clearly with people who are not specialists. Metastasis learning is one of the unresolved issues and this issue leads to the acquisition of versatility. Due to Metastasis learning, introduction of pleasant and unpleasant to AI is effective. In this paper, pleasant has nature of "dissolution of unpleasant", and therefore pleasant is based on unpleasant. It brings distinction to reward by unpleasant and ability to distinguish brings AI to unique purpose for each task.