A method for producing a conductive polymer film using an apparatus comprising a prism having a working electrode, a light-emitting means, a light probe disposed on both sides of the prism, a container having an electrolytic solution containing a conductive-polymer-forming monomer and a dopant, a counter electrode immersed in the electrolytic solution, a power supply connected to a working electrode and the counter electrode, and a controller connected to the light probe and the power supply means. The method comprises determining an absorption spectrum from light reflected by the conductive polymer film, storing the relation between the absorbance of the conductive polymer film obtained from the absorption spectrum and a parameter of the conductive polymer film in the controller, and controlling current supply to the electrodes based on the relation of the absorbance and the parameter to obtain a desired parameter.