A CPU of a robot control device calculates load torque based on the inertia force, centrifugal force or Coriolis force, gravity force, friction torque, and actuator inertia torque applied to a joint axis of each link, each time an orientation parameter indicative of the link position and orientation allowed by a redundant degree of freedom is sequentially changed, under a constraint of end-effector position and orientation as target values. The CPU obtains the link position and orientation at which the ratio of the load torque to the rated torque of a rotary actuator provided for each joint is minimized, while the orientation parameter is being changed, and provides a feed-forward value that gives rise to each load torque obtained when the ratio of the load torque to the rated torque of the rotary actuator is minimized, to a control command generated to the rotary actuator of each joint axis for achieving the end-effector position and orientation as target values.