Permanent Magnet Synchronous Motor has advanced by the request for high efficiency and high power density. In a design for each application, a special design which satisfies each request is required. Thus, earlier design period and higher design skill are required. Adding that, it is important a designer has a grasp of the relationship between the requests and the motor mechanical parameters. In this paper, an automatic design method for an example of a special design is described. In this method, it is possible to obtain the motor mechanical parameters, and minimum volume structure can be obtained.