This paper aims to clarify the mechanism of formation of the vegetable producing area in Okabe Town of Saitama Prefecture and the conditions of its sustainable development. The decline of sericulture and the development of vegetable production have close relationship with the change of socioeconomic environment surrounding the local community. And the improvement of agricultural management environment in this area has promoted the formation of vegetable producing area. At the level of farm household, internal farming conditions of each household had the strongest influence over the farmer's decision-making, such as arable-land area; farm labor force, especially male farm workers; and successors of agricultural management. Furthermore, when the successor got married and took part in the agricultural management, or when the head of household was replaced by younger generation, the management policy is changed and the introduction into a new management sector is encouraged. The formation of vegetable producing area in Okabe Town experienced three stages. First, in succeeding the introduction of broccoli production by an enterprising farmer, many farmers introduced broccoli one after another. Second, the individual farm households organized moderately-linked groups of farm households to secure more favorable conditions in the production and sales of agricultural products, to establish cooperative and complementary relationship between the farm households or settlements and to sustain the development. Third, they organized the Council for the Unified Shipment of Fruits and Vegetables within the jurisdiction of the Agricultural Cooperative. Thus, the individual vegetable farms have been organized spatially, and the space for vegetable production has expanded from “point” (individual farm) to “plane” (vegetable producing area).