In a cell manufacturing method in which a main operator, who carries out main operations that includes a plurality of steps in which parts are attached to a workpiece, is moved with the workpiece so as to transit a plurality of stations at which auxiliary steps related to the main operation are carried out. A main car on which a workpiece is mounted and on which a main operator rides and a subsidiary car on which a subsidiary operator rides, the subsidiary operator preparing at least a portion of the parts and/or jigs that are necessary for the main operation, are used. The main car automatically travels on a predetermined travel path that transits a plurality of stations, and the subsidiary car travels together with the main car so as to enable transferring parts and/or jigs between the main car and the subsidiary car.