Anionic polymerization of acrylonitrile was achieved by constant-potential electrolysis via direct electron transfer to the monomer. The reduction peak potential in the (C4H9)4NBF4-CH3CN electrolyte-solvent system was measured by cyclic voltammetry. On the other hand, dimethylformamide-metal salts were not found suitable for the direct electron-transfer process in our system. Polymers produced both anodically and cathodically were found to contain cyclized structures.