A picking system comprising: a conveying device that conveys workpieces; an articulated robot that includes a holding part and articulations, wherein the robot performs, by using the holding part, a holding operation by picking a workpiece conveyed by the conveying device and holding the workpiece and moves the articulations to perform moving operation for moving the workpieces held by the holding part to a predetermined place; an image capturing device that is provided at an upper stream side of the conveying device from the robot to continuously capture a transport path of the conveying device; a control device that detects the workpieces on the transport path on the basis of an image captured by the image capturing device, and instructs the robot to perform the holding operation on the detected workpieces, and an auxiliary image capturing device that is provided near the robot or directly on the robot and captures the workpieces to be held by the robot the control device including: an abnormality detecting unit that detects abnormality of the captured workpieces by comparing the area of the workpieces measured from the image captured by the image capturing device to stored information indicating the area of non-defective workpieces; an overlapping detecting unit that performs, when abnormality of the workpieces is detected by the abnormality detecting unit, an edge detection process on an image of the workpiece detected to have abnormality captured by the auxiliary image capturing device, to detect overlapping of the workpieces by comparing the edge detected to stored reference edge patterns; and an operation instruction unit that instructs the robot, when the overlapping of the workpieces is detected by the overlapping detecting unit, to perform the holding operation on a top one of the workpieces that has been detected to be overlapping, wherein the auxiliary image capturing device has a higher resolution than the image capturing device, and starts, when the abnormality of the workpieces is detected by the abnormality detecting unit, to capture images of the workpieces detected to have abnormality a conveying device that conveys workpieces; an articulated robot that includes a holding part and articulations, wherein the robot performs, by using the holding part, a holding operation by picking a workpiece conveyed by the conveying device and holding the workpiece and moves the articulations to perform moving operation for moving the workpieces held by the holding part to a predetermined place; an image capturing device that is provided at an upper stream side of the conveying device from the robot to continuously capture a transport path of the conveying device; a control device that detects the workpieces on the transport path on the basis of an image captured by the image capturing device, and instructs the robot to perform the holding operation on the detected workpieces, and an auxiliary image capturing device that is provided near the robot or directly on the robot and captures the workpieces to be held by the robot the control device including: an abnormality detecting unit that detects abnormality of the captured workpieces by comparing the area of the workpieces measured from the image captured by the image capturing device to stored information indicating the area of non-defective workpieces; an overlapping detecting unit that performs, when abnormality of the workpieces is detected by the abnormality detecting unit, an edge detection process on an image of the workpiece detected to have abnormality captured by the auxiliary image capturing device, to detect overlapping of the workpieces by comparing the edge detected to stored reference edge patterns; and an operation instruction unit that instructs the robot, when the overlapping of the workpieces is detected by the overlapping detecting unit, to perform the holding operation on a top one of the workpieces that has been detected to be overlapping, wherein the auxiliary image capturing device has a higher resolution than the image capturing device, and starts, when the abnormality of the workpieces is detected by the abnormality detecting unit, to capture images of the workpieces detected to have abnormality an abnormality detecting unit that detects abnormality of the captured workpieces by comparing the area of the workpieces measured from the image captured by the image capturing device to stored information indicating the area of non-defective workpieces; an overlapping detecting unit that performs, when abnormality of the workpieces is detected by the abnormality detecting unit, an edge detection process on an image of the workpiece detected to have abnormality captured by the auxiliary image capturing device, to detect overlapping of the workpieces by comparing the edge detected to stored reference edge patterns; and an operation instruction unit that instructs the robot, when the overlapping of the workpieces is detected by the overlapping detecting unit, to perform the holding operation on a top one of the workpieces that has been detected to be overlapping, wherein the auxiliary image capturing device has a higher resolution than the image capturing device, and starts, when the abnormality of the workpieces is detected by the abnormality detecting unit, to capture images of the workpieces detected to have abnormality