PURPOSE: To obtain an electroconductive self-doped polymer which can be rapidly doped or dedoped, consisting of repeating units a specified proportion of which have at least one covalently bonded Bronsted acid group and therefore having a main chain structure which can give a π-electron conjugated system.

CONSTITUTION: This electroconductive self-doped polymer consists of a number of monomer units 0.01W100mol% of which have a covalently bonded Bronsted acid group and a π-electron conjugated system along the main chain. In said self-doped polymer, it is preferable to select a monomer unit having a covalently bonded Bronsted acid group from the repeating structural units of formulas I and II, wherein Ht is a hetero group, Y1, Y2, Y3 and Y4 are selected indepen dently of each other from the group consisting of hydrogen and -R-X-M, wherein R is a 1W10C linear or branched alkyl, ether, ester or amide component, X is an anion of a Bronsted acid and M is an atom which can give a positive monovalent counter ion when oxidized.