An apparatus and method for manufacturing a highly efficient flexible thin metal film-laminated strip by improves adhesiveness between a polyimide strip and a thin metal film, and removes stress from thin films laminated through magnetron sputtering, which is a dry deposition process. The stress-free flexible circuit board manufacturing method includes the steps of: a) depositing a seed layer on the substrate using the magnetron deposition source; b) depositing a compressive thin film using the single magnetron deposition source arranged next to the magnetron deposition source; c) depositing tensile thin film using the dual magnetron deposition source arranged next to the single magnetron deposition source; and d) repeating the steps b) and c) so as to sequentially and alternately deposit compressive thin films and tensile thin films thereby obtaining a thick film with a desired thickness.