The invention relates to a method for electrolyzing flat elements as printed circuit board and printed circuit film in pass-through treating device, and a relative device, wherein it uniformly treats the treated matter in the full surface, or forming surface, and the through whole and blind hole; the fills the blind hole, while it combines the flowing directions between impulse current and the electrolyte solution. The invention uses large distance between anode and cathode (20, 21) whose upper limit is 600mm.