We proposed new arm-wheel hybrid robot “Souki-II” which consists of a body, a pair of large bore wheels which sandwich the body and rotates around the same axis from the body, articulated hand attached to the body, and free caster attached around the wrist of the hand. Souki-II showed high terrain adaptive motion by using the large bore wheels and free caster of the hand. We also showed that the mobility can be enhanced when multiple units are connected together. Souki-II can also take the mode of a manipulator. For the joint mechanism of the Souki-II, we introduced a unit actuator system and a cover member with spiral groove to pass the electric harness and to assist in heat dissipation. From the experiments of the constructed models, we could demonstrate the innovative performance of the proposed Souki-II system.