To provide a leg type travelling system capable of climbing and descending a slope and stairs as well as rough terrain by operating it forward, backward, and vertically while keeping all legs in parallel for each other during travelling by merely rotating and driving a shaft of a hip joint.

The rotating and driving shaft is used as the hip joint. A plurality of arms are extended in the radial direction from the hip joint. A knee joint is put in parallel with the hip joint at an arm tip. A landing leg is supported around a shaft of the knee joint to rotate it freely. A gear or a sprocket is put on the shaft of the hip joint and is fixed to a travelling device main body. This gear or sprocket is connected with a gear or a sprocket supported on the knee joint and fixed to one end of the landing leg by a power transmission means having a ratio of the numbers of teeth of 1 vs. 1. This system is provided with at least three hip joints to climb or descend a slope and stairs as well as rough terrain by operating it forward, backward, and vertically while keeping all legs in parallel for each other during travelling by merely rotating and driving the shaft of the hip joint. Moreover, travelling and steering are continuously performed by changing a ratio of rotation speed of right and left hip joints.