In this paper, we propose an object tracking system using an arm robot and two pan-tilt cameras. By combining these devices, we realize the high speed and wide range object tracking method. In order to trace an object, we must find the pattern of object in camera images. To perform fast object detection, we employ a method of the particle filter which describes object location probabilistically. In experiments, our tracking system can trace objects which move surround of the system, and we can confirm effectiveness of proposed method.