It is becoming very important to develop manufacturing technologies which win in a global economic competition. In this study, we discuss replacement possibility from expert skills to technologies. Competitive superiority of the Japanese manufacturing industries is maintained at a higher position by understanding a current situation about the expert skills and the technologies which can survive in the next generation. As a result of understanding such a situation, a policy for personnel training is expected to identify. We want to solve the problem how the personnel training of the engineer should do, by visualizing the replace and modeling process to the technology of the expert skill process. We therefore classify existing expert skills, on the basis of a assumption that all expert skills can't be always replaced to technologies. It will be clarified by this classification whether this replacement possibility depends on a point of view of the originality and differentiation or economic issues.