A robot system comprising: a robot that includes a robot arm and a first camera , wherein the first camera is a stereo camera and is installed on a head portion of the robot; a second camera that is installed separately from the robot; and a control device configured to control the robot and the second camera, wherein the control device includes a processor , the second camera is installed to image a calibration position that is outside a field of view of the first camera while the first camera images a work area (WKA) where the robot arm performs a work, and the processor is configured to (a) drive a joint (J0) of the robot to image the calibration position by the first camera before the work is executed in the work area, (b) image with the first camera a calibration pattern installed at the calibration position, to acquire a first pattern image and image with the second camera the calibration pattern installed at the calibration position, to acquire a second pattern image, (c) execute a calibration process for obtaining a second calibration data which is calibration data of the second camera using the first pattern image, the second pattern image, and a first calibration data which is known calibration data for the first camera, and (d) execute the work in the work area while the first camera images the work area after executing the calibration process and executes an operation using the robot arm in the field of view of the second camera while the second camera images in the field of view of the second camera. a robot that includes a robot arm and a first camera , wherein the first camera is a stereo camera and is installed on a head portion of the robot; a second camera that is installed separately from the robot; and a control device configured to control the robot and the second camera, wherein the control device includes a processor , the second camera is installed to image a calibration position that is outside a field of view of the first camera while the first camera images a work area (WKA) where the robot arm performs a work, and the processor is configured to (a) drive a joint (J0) of the robot to image the calibration position by the first camera before the work is executed in the work area, (b) image with the first camera a calibration pattern installed at the calibration position, to acquire a first pattern image and image with the second camera the calibration pattern installed at the calibration position, to acquire a second pattern image, (c) execute a calibration process for obtaining a second calibration data which is calibration data of the second camera using the first pattern image, the second pattern image, and a first calibration data which is known calibration data for the first camera, and (d) execute the work in the work area while the first camera images the work area after executing the calibration process and executes an operation using the robot arm in the field of view of the second camera while the second camera images in the field of view of the second camera. (a) drive a joint (J0) of the robot to image the calibration position by the first camera before the work is executed in the work area, (b) image with the first camera a calibration pattern installed at the calibration position, to acquire a first pattern image and image with the second camera the calibration pattern installed at the calibration position, to acquire a second pattern image, (c) execute a calibration process for obtaining a second calibration data which is calibration data of the second camera using the first pattern image, the second pattern image, and a first calibration data which is known calibration data for the first camera, and (d) execute the work in the work area while the first camera images the work area after executing the calibration process and executes an operation using the robot arm in the field of view of the second camera while the second camera images in the field of view of the second camera. <EOS>