WORKPIECE PICKING DEVICE

A workpiece picking device capable of correctly detecting the size of a workpiece. The picking device has a robot capable of picking the same kind of workpieces contained in a work container, a robot controller for controlling the robot, a video camera positioned above the work container so as to widely image the workpieces and an image processor for processing an image obtained by the video camera. The three-dimensional position and posture of each workpiece is measured by a three-dimensional vision sensor arranged on a wrist element of the robot.