A walking robot having joints which move using a torque servo, a posture of the robot being stably controlled, and a method of controlling a posture of the robot. It is possible to maintain a stable angle of the upper body while keeping an erect posture and balance using the COG of the robot and the inclination and the direction of the upper body and the pelvis of the robot, even in an external variation including external force or an inclination angle of the ground. Even in a state in which terrain information is not known in advance, the robot may keep an erect posture in a direction of gravity. Even when a plane where the robot stands is gradually inclined, the postures of the upper body and the legs of the robot may be kept while actively changing the angle of the ankle joint.