This multi-joint link mechanism has a driving joint driven by a driving source and a follower joint driven by the movement of the driving joint. First, an open-loop link mechanism that allows the position and pose of a workpiece to be varied is selected from a multi-joint link mechanism. The amount of movement/rotation of each of the joints constituting the selected open-loop link mechanism is derived. The derived amounts of movement/rotation of each of the joints of the open-loop link mechanism are set as fixed values to derive the amount of movement/rotation of each of the joints of a closed-loop link mechanism composed of non-selected joints and at least some of the joints of the open-loop link mechanism.