Japan’s forest industry operates in mountainous regions rather than hilly areas. The forest road density is also low, and it is not easy to develop new roads and maintain them. Therefore, the work of moving about and transporting heavy loads over irregular mountain forest terrain far from roads is still hard labor performed by humans. Even today, a little technical development has been done to assist in this work. The authors have proposed and developed a machine that can travel and carry heavy loads in irregular mountain terrain that corresponds to the characteristics of mountain forests and the forestry industry in Japan. This report describes a novel suspension system that applies the load equalization pulley suspension mechanism (LEPS) to a crawler track roller suspension mechanism. Specifications and performance requirements taken from previous experiments and developed machines were brought together to design and develop a full-sized prototype machine. Proving tests such as moving over obstacles were done with this prototype and its performance was evaluated. The utility of the machine proposed in this report was shown.