A robot handling system using a robot hand to convey a workpiece, provided with a first wrist element at a front end of an arm of the robot, a second wrist element perpendicular to this, a third wrist element perpendicular to this, and a connecting means connecting the third wrist element and a hand body of the robot hand, the hand body being arranged so that an inertia moment of the hand body about a vertical axial line becomes larger than the inertia moments of the hand body about two mutually perpendicular horizontal axial lines, the connecting means connects the third wrist element and hand body so that a third axial line of the third wrist element and the hand body are arranged in a horizontal plane, and a posture of the hand body is changed about the vertical axial line in the state with the third axial line of the third wrist element arranged in a horizontal plane. Due to this, the robot hand can be made to rotate over the limit of the allowable inertia moment.