The lumbar part of a robot as a controlled-object point where the mass is moved to the largest extent is set as the origin of a local coordinate, an acceleration sensor is disposed at the controlled-object point to directly measure the attitude and acceleration at that position to control the robot to take a stable posture on the basis of a ZMP. Further, at each foot which touches the walking surface, there are provided a floor reaction force sensor and acceleration sensor to directly measure a ZMP and force, and a ZMP equation is formulated directly at the foot nearest to a ZMP position. Thus there can be implemented a stricter and quick control of the robot for a stable posture.