Akira Inoue and Tetsuji Abe Recently, several distributed applications have been proposed, each of which consists of many separate components. In these applications, because operations are distributed to the components, their performance is improved. However, the performance is not always good. This is because the configuration of the components is fixed, whereas obtaining a suitable configuration requires a flexible response to several factors.So, in this paper, we propose an agent framework for a dynamically distributed application which consists of many mobile agents. The agents change their configuration dynamically using migration to improve the performance of the application depending on variations in the environment such as the network condition and the load of the computer.To support these activities, the framework provides agents with many services, which enable them to communicate with other agents seamlessly even during migration over the network.We also implement the agent framework and a prototype application. Then we show the potency of the dynamically distributed application by evaluating the dynamic transformation of agents' configuration, and show the effectiveness of the framework by evaluating the migration process.