A robot system includes robot, an image capture device, a plurality of illumination devices, and a control device. The robot is configured to perform a predetermined work on a to-be-processed material. The image capture device is configured to capture an image of the to-be-processed material and has a dynamic range. The plurality of illumination devices are configured to illuminate the to-be-processed material. The control device is configured to control at least one illumination device among the plurality of illumination devices to keep an amount of light received by the image capture device within the dynamic range of the image capture device.