1. A robot system comprising: a plurality of robots arranged along a line; a control device configured to control the plurality of robots; a common work table on which the plurality of robots are configured to work; and a calibration device configured to, based on a position of a first robot having a calibrated coordinate relative to a position of a second robot among the plurality of robots, calibrate a coordinate of the second robot, wherein the calibration device is configured to calibrate a coordinate of an uppermost stream robot among the plurality of robots based on a position of the uppermost stream robot relative to a position of the common work table, the uppermost stream robot being configured to work at an uppermost stream position of the line, and the calibration device is configured to calibrate a coordinate of an intermediate robot among the plurality of robots based on a position of the uppermost stream robot relative to the position of the common work table, the intermediate robot being disposed at a lower stream position on the line than the position of the uppermost stream robot, wherein the calibration device is configured to calibrate a coordinate of a lowermost stream robot based on a position of the lowermost stream robot relative to the position of the common work table, the lowermost stream robot being configured to work at a lowermost stream position on the line, and the calibration device is configured to calibrate the coordinate of the intermediate robot based on the position of the lowermost stream robot relative to the position of the intermediate robot disposed at an upper stream position than the position of the lowermost stream robot, and wherein the calibration device is configured to use a calibration result of the uppermost stream robot and a calibration result of the lowermost stream robot to calibrate the coordinate of the intermediate robot.