In this study, the author analyzes the development of full-time farms in the urban fringe of the Tokyo metropolitan area and clarifies their sustainability on a micro-scale using the example of the Takabatake area, Saitama city, Saitama Prefecture. In this area, many full-time farms are maintained by diversified farming. Each farm has adopted new crops and expanded diversified farming to respond to economic and social changes. In this area, the physical, social, institutional, and regional environments have made it possible for farms to adopt a succession of new crops and maintain diversified farming. In particular, the physical environment characterized by lowlands and plateaus has made it possible to combine paddy rice and vegetable production. The social environment characterized by homologic unification has made it possible to supplement the shortage of labor. Access to markets in the metropolitan area has made it possible to adopt commercial crops like arrowheads and flowers. As a result of the introduction of various crops, each farm participates in a division of labor and leveling of income and labor supply. Furthermore, diversified farming helps each farm not only to level income and labor supply but also to incubate successors. In this area when adopting new crops, farmers have handed over the new business to their successors. As a result, the successors have developed the business in their own way and maintained full-time farms. In the Takabatake area most successors had engaged in business in markets for agricultural products before engaging in agricultural management. This has influenced farm management in the Takabatake area. Concretely speaking, they developed networks with various markets and then introduced new markets to the Takabatake area. As a result, most farms send various crops to various markets. Each farm has overcome the risk in successors' adopting new crops and new markets by maintaining traditional crops.