A controlling unit obtains an error in position and orientation of each joint of a robot. The controlling unit uses an error component in a driving direction of an actuator included in the error in position and orientation ui of the joint to obtain a first correction quantity, to obtain a residual error excluding the error component in the driving direction of the actuator from the error in position and orientation of the joint, and to obtain—an error in position and orientation of the end point of the robot based on the residual error of each joint. The controlling unit uses the error in position and orientation of the joint based on the error in position and orientation of the end point of the robot to obtain a second correction quantity Δqi, and uses the first correction quantity and the second correction quantity to correct a joint instruction value.