The Fukushima Daiichi Nuclear Power Station was damaged by the Great East Japan Earthquake on March 11, 2011. Since it has been difficult for workers to approach the reactor buildings due to high radiation environment, remote operated robots are required on behalf of workers. For this reason, we have developed a quadruped walking robot which can walk on uneven terrain and carry loads such as various tools. When the arm for handling loads is mounted on the robot, the conveyable load is decreased by weight of the arm. Therefore, we realized the unloading motion by using two of its legs as handling arms. This enables to carry the load which is equal to the maximum payload of the robot. Moreover, carrying and unloading a long or heavy load, which a single robot can’t carry, was realized by two cooperative controlled robots.