TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The sulfonic acid has greater than or equal to 7C hydrocarbon group. The protonic acid group is a sulfonic acid group, carboxyl group, phosphoric acid group, or sulfuric acid group. The molecular weight adjusting agent is an aniline derivative having a substituent at its 4th position, a thiol compound, a disulfide compound, or an alpha-methylmethylene dimer. The thiol compound is a thiol compound having greater than or equal to 4C hydrocarbon group. The disulfide compound is a disulfide compound having greater than or equal to 2C hydrocarbon group. The phase transfer catalyst is a quaternary ammonium salt, phosphonium salt, or crown ether compound. Preferred Parameter: The amount of sulfonic acid used is 0.01-10 moles/mole of aniline or its derivative.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The oxidation polymerization is carried out using a persulfate as the oxidizing agent. Preferred Parameter: The amount of polymer compound having the protonic acid group is an amount by which the protonic acid group becomes 0.05-20 moles, based upon 1 mole of the aniline or its derivative. The amount of conductive aniline is 0.01-100 pbw, based upon 100 pbw of the organic polymer. Preferred Material: The organic polymer is a component(s) consisting of rubbers, polyolefin resins, polyester resins, polyamide resins, epoxy resins, polyimide resins, or fluororesins. EXAMPLE - In toluene (100 g), aniline (2 g), dodecylbenzene sulfonic acid (4.2 g), Solsperse 26000 (RTM; polyacrylic acid derivative) (1.0 g), and 4-methylaniline (0.03 g) were dissolved. Distilled water (50 g), in which 6 N hydrochloric acid (3.58 ml) was dissolved, was added. Tetrabutylammonium bromide (180 mg) was added to the mixed solution. The result was cooled to less than or equal to 5degreesC, then distilled water (30 g), in which ammonium persulfate (5.4 g) was dissolved, was added. The resultant mixture was oxidative polymerized at less than or equal to 5degreesC for 5 hours, then toluene was distilled off in vacuum. The polyaniline precipitate formed in the water was obtained by filtration, and rinsed with water to obtain polyaniline.