A ubiquitous computing environment entails numerous embedded devices with enough computational power. Such distributed computing resources can cooperate to create applications which support users' everyday lives. Such an environment requires robust middleware that can handle a large quantity of messages, such as event data or sensor data are occurred between devices. However, the lack of middleware technologies with such functionalities has been making It difficult to create ubiquitous computing applications that we can depend on In their everyday life. In this paper, we propose a novel middleware, named RT-Dragon, which can handle numerous messages with robustness. RT-Dragon can work effectively on systems both real-time and non-realtime runtime because of the mechanism of two level priority-based task processing. In this paper additionally, we evaluate the effectiveness of RT-Dragon on non-RT runtime.