1. A robot apparatus comprising: a conveying robot that holds a target to be conveyable to a goal position; an image pickup unit that picks up an image of the goal position and the target included in a field of view and generates image data; a goal-image storing unit that stores, according to sensitivity represented by an amount of change of a pixel value at the time when the target aligned with the goal position in the image data at a pixel level is displaced by a displacement amount at a sub-pixel level, goal image data in a state in which the target is arranged; a target detecting unit that calculates a coincident evaluation value of the target on the basis of comparison of the image data including the image of the target, which is held by the conveying robot, generated by the image pickup unit and the goal image data stored by the goal-image storing unit and detects positional deviation of the target with respect to the goal position on the basis of the coincidence evaluation value; and a conveying-robot control unit that controls the conveying robot to convey the target held by the conveying robot in a direction in which the positional deviation detected by the target detecting unit is eliminated.