Thanks to rapid advance and penetration of IoT devices, it is becoming possible to sense almost every information of real-world. This urges us to utilize data streams continuously generated from IoT devices in real-Time. In this paper, aiming to locally process data streams by using computational resources of IoT devices, we propose middleware for IoT devices where the devices process data streams in real-Time and in a distributed manner. The proposed middleware provides four functions: (1) distribution of tasks issued by application software into sub-Tasks and distributed execution of the sub-Tasks over multiple IoT devices, (2) distribution of data streams over IoT devices, (3) real-Time analysis of the data streams, and (4) seamless integration of sensors and actuators. We have implemented a prototype of the proposed middleware for Raspberry Pi and show its basic performance.