The present invention relates to a method of surface treatment, a method for forming circuit lines, a printed circuit board formed thereby, and an apparatus for forming circuit lines on a substrate, wherein fine circuit lines are formed simply, rapidly, and economically. The method for forming circuit lines of the present invention comprises: (a) selectively applying a surface treatment solution which includes an alkali metal compound on a base film in accordance with circuit patterns by a discharging method; (b) applying a conductive ink which includes metal nanoparticles in accordance with the surface-treated circuit pattern; and (c) curing the base film on which the conductive ink is applied under a reduction atmosphere lines.