Recently, development of mobile robots is actively pursued. These robots are expected to work in various situations such as rescue and exploration. Therefore, we developed a leg using pneumatic rubber artificial muscles and constructed a model of the legs. Then, we developed a hexapod robot which can support its weight mechanically even without power supply using these legs. The robot supported about 4 times as much load as its own weight floating idling legs in experiment. Furthermore, the robot walked with load. And we concluded that the cause of reduction in a walking speed is friction of a transverse direction to a direction of movement of the legs. In the future, we plan to decrease unnecessary friction of the leg, and mount a compressor, a power supply, and a tank in the robot.