An ambulatory robot including a lower body part having two or more legs and an upper body part installed on an upper end of the lower body part and capable of performing positional displacement by moving the lower body part, includes slope-detection means for sensing a slope of a floor, rotating means installed on a bottom surface of each of the two or more legs, and control means for controlling a motion of the ambulatory robot using the lower and upper body parts, wherein the control means controls a speed of revolution of the rotating means based on the slope of the floor, and controls the motion of the ambulatory robot so that the positional displacement of the ambulatory robot is performed by any of running, walking and sliding, depending on the controlled speed of revolution.