PURPOSE: To improve the degree of freedom in constituting a device group by recording the data from polishing condition judging computers in data carriers provided on pallets, moving them on conveyance lines in conjunction with works, and machining the works with the data on individual device based on the recorded data of the devices.

CONSTITUTION: Conveying vehicles 2a-2d carrying pallets 3a-3d (referred to as 3 hereafter) mounted with works respectively are moved on conveyance lines 1a-1d by commands of a COM 5. Data carriers 4a-4d (referred to as 4 hereafter) are mounted on the pallets 3. The data condition-judged/measured by a work maintenance/polishing condition determination station A and a work measurement station B respectively are recorded in the data carriers 4 from computers COM 1, COM 2. The pallets 3 are conveyed to a machining/measuring device group E, and individual devices execute their responsible processes based on the data in the data carriers 4 respectively.