A polishing method and polishing device capable of improving the flatness of wafers. When a wafer is brought into contact with a wafer holding board and the surface to be polished of the wafer is pressed and abraded against an abrasive cloth on a polishing surface plate for polishing, the wafer is vacuum-sucked and held at its surface to be polished to come into contact with the wafer holding board with the center of the wafer' contact surface first so that the wafer's contact surface forms a convex surface in the vicinity of a portion including appropriate points on the contact surface within a region taking up at least 50% of the entire contact area and surrounding the center of the contact surface.
