A workpiece picking system including: a robot; a hand, attached to a hand tip portion of the robot, for picking workpieces; a three-dimensional sensor, attached to the hand tip portion, for acquiring positional information of a three-dimensional point group in a partial region in a container; a workpiece state calculation unit which calculates a position and posture of a workpiece based on positional information of a three-dimensional point group in an acquired first partial region; a data acquisition position calculation unit which calculates a robot corresponding to a second partial region where positional information is to be acquired next, based on the positional information of the three-dimensional point group in the acquired first partial region; and a control unit which controls the robot and the hand based on the calculated position and posture of the workpiece and based on the calculated robot position corresponding to the second partial region.