To polish and eliminate a membrane while correcting polishing unevenness by uniformly pressing the whole surface of a substrate and distributing the pressure in conformity to the polishing unevenness generated with the progress of polishing, and to cope with the large size of the substrate without enlargement and complication, dispensing with a special driving means for controlling the polishing pressure.

In polishing the membrane formed on the substrate 1 by relatively moving the substrate 1 and a polishing sheet 3 attached to a surface table 4, while applying pressure, the substrate 1 is pressed by a large number of loads 5 supported by a load holding member 6 on the substrate back face side. According to the membrane thickness unevenness of the substrate 1 measured by a membrane thickness measuring apparatus 11, the arrangement of load distribution allowing the elimination of the membrane thickness unevenness is computed and determined by a load distribution computing device 12. On the basis of the arrangement of load distribution, different kinds of loads 5 (5a, 5b, etc.), are combined and arranged at the load holding member 6 to obtain the polishing pressure suitable for eliminating the polishing unevenness to carry out polishing.