The purpose of this study is to clarify the developmental characteristic of small rental shops, and to clarify the function of urban block to incubate young shopkeepers . The results are as follows. 1.The urban block collecting small and cheap rental shops has the function to incubate young shopkeepers setting up business on their account. 2.The small rental shops have the types of the developmental characteristic. They are the type to increase shops in number near at central district, the type to move at central district searching wider shop and more customers, and the type to increase shops in a wide area searching various customers.