Soryu-4 is a modular robot developed to move in narrow and unstructured environments. It consists of dust/water-proof modules covered with crawler belts, and can adapt its posture in order to overcome obstacles such as stairs, ditches, ducts, debris and more. The modules can be configured to bring different sensors, devices and cameras, thus extending its applicability to urban, industrial, outdoor or unstructured scenarios. In addition, Soryu-4 requires practically no set-up time, making it an ideal robot for fast-response search & rescue missions in disaster-stricken areas, or remote inspection in potentially hazardous sites.