In regions prone to disasters, the instability of the ground and risk of collapse are the primary factors limiting rescue operations. For ensuring the safety and effectiveness of these operations, a remotely controlled search robot is desired. Accordingly, projects are being conducted for exploring rapid and comprehensive rescue response by deploying a mass of small searching robots from aerial drones. As the payload of drones is limited, the robots must be small and lightweight; however, mobile robots with high mobility on rough terrain typically possess complex structures and tend to be heavy. In this study, we propose a novel mobile mechanism with a simple structure and high mobility that is composed of an elastic track belt, which deforms to adapt to irregular obstacles and is driven by a single sprocket. The system was evaluated and compared with a general wheel robot on the basis of its performance in step-climbing tests. The ratio of the maximum height climbed by the proposed mechanism to its wheel diameter is 145%, and its maximum height is 2.9 times than that achieved by the conventional robot. Furthermore, the results are superior when compared to those of the conventional continuous-track-type mechanisms. Overall, our method can be applied to any miniaturized robot that is required to possess high mobility on rough terrains.