Method for manufacturing processed article, method for manufacturing semiconductor device, and apparatus for manufacturing processed article

The method for manufacturing a processed article includes: a preparation step of preparing an object to be processed (1) including at least a lead frame in which a groove portion (5) is formed in advance along a position to be cut; a surface layer removal step for partially removing a surface layer portion (3c) in the object to be processed (1), said surface layer portion (3c) having the groove (5) formed therein, prior to cutting the object to be processed (1); and a plating step in which, prior to cutting the workpiece (1), the workpiece (1) from which the surface layer portion (3c) has been partially removed is subjected to a plating treatment, and the surface layer portion (3c) has been partially removed from the workpiece (1) before the surface layer removal step is performed. The surface layer portion (3c) includes a cut region (3m) removed by cutting the object to be processed (1), and a non-cut region (3n) located between the cut region (3m) and an opening end (5c) of the groove portion (5), and in th