PURPOSE: To provide the process for producing the conductive thin film useful as a functioning material in electric, electronic and other fields by which film thicknesses are controlled with high orderliness and dopants are stably maintained.

CONSTITUTION: A high polymer having a π electron conjugation system along the main chain of a polymer of a thiophene compd. and amphoteric moleculer are developed in a developing solvent to prepare a soln. mixture for developing the Langmuir Blodgett (hereafter abbreviated as LB) film mixture. A monomolecular film mixture is accumulated on a supporting substrate by the LB method to form the LB film mixture on the surface of the supporting substrate. This supporting substrate is immersed into a soln. which contains an electrolyte and does not dissolve the LB film. A counter electrode (cathode) is installed with this supporting substrate as an anode and a current is passed thereto, by which the anion is electrochemically doped into the LB film mixture and the conductive LB film mixture is produced.