The invention relates to a self-doping type electrically conducting polymer comprising an isothianaphthene or thiophene skeleton where the polymer chains are crosslinked preferably through a sulfone bond which is imparted with water resistance and solvent resistance; a production process thereof; an electrically conducting composition film obtained by coating a composition containing the self-doping type electrically conducting polymer on a substrate and heating it; a product coated using the composition; and an electronic device containing the self-doping type electrically conducting polymer.