Method for manufacturing printed wiring board

A method for manufacturing a printed wiring board, the method comprising:

• an etching step that comprises:
• preparing a conductor-clad base material continuous in a certain direction, supporting and carrying the conductor-clad base material along the certain direction, the conductor-clad base material having an insulating layer and one or more conductive layers formed on main surfaces of the insulating layer;
• and subjecting a predetermined region of a conductor layer of one main surface of the conductor-clad base material to an etching process thereby to form a wiring pattern to be of a product and an inspection pattern to be used for inspection;
• a measuring step that measures a line width of the inspection pattern after the etching step;
• and
• a control step that controls an etching condition in the etching step based on the measured line width;
• wherein the inspection pattern comprises a plurality of line-like patterns parallel to one another along the certain direction, and wherein each of the line-like patterns has a predetermined line width;
• wherein, when each difference between line widths of the plurality of line-like patterns is less than a predetermined value, then the control step controls the etching condition based on the line widths of that plurality of line-like patterns, whereas when each difference between line widths of the plurality of line-like patterns is more than or equal to the predetermined value, then the control step determines that plurality of line-like patterns as not being the inspection pattern and stops controlling the etching condition based on the line widths of that plurality of line-like patterns and continues an immediately previous control.