A robot system is provided with a three-dimensional sensor which acquires three-dimensional information of an object, and a robot which includes a gripping device for gripping an object. The robot system uses first three-dimensional information which relates to a state before an object is taken out and second three-dimensional information which relates to a state after an object is taken out as the basis to acquire three-dimensional shape information of an object, and uses the three-dimensional shape information of the object as the basis to calculate a position and posture of the robot when an object is placed at a target site.