A vertical component or the like of a floor reaction force moment to be applied to a robot 1 is defined as a restriction object amount, and the permissible range of the restriction object amount is set. A provisional motion of the robot that satisfies a predetermined dynamic balance condition is determined on a predetermined dynamic model, and if a restriction object amount determined by the provisional motion deviates from the permissible range, then the motion of a desired gait is determined by correcting the provisional motion by changing the angular momentum changing rate of the robot from the provisional motion while limiting the restriction object amount to the permissible range on the dynamic model.