We aim at the development of rescue robots which are driven by ultra high pressure hydraulic small actuators. They are small-sized and have simple mechanisms, and can realize high-powered operations. This report shows the designs of two high powered small rescue robots-Jack Robot and Cutter Robot-and the results of the field tests carried out to verify in the possibilities. We carried out the field tests in the three types of field; collapsed house type, rubble type and traffic accident type. As the experimental results, the potential of high-powered small robots in disaster areas were shown.