An electrophotographic toner for negative charging comprises an acrylamide copolymer containing sulfonic acid groups as a charge-controlling agent for negative charging and a quaternary ammonium salt having an oxyacid anion as a charge-controlling assistant, a fixing resin and a colorant. The quaternary ammonium salt used as the assistant is incompatible with a fixing resin but dispersible therein. The toner provides a sharp distribution of the charge quantity so that formation of highly charged toner particles which do not contribute to development and lowly charged toner particles which are easily scattered is effectively prevented.