The present invention is to provide a charge controlling agent and negatively chargeable toner that do not contain any toxic metal, are essentially free from the risk of evoking ignition or explosion, and can exhibit a high charge amount and rapid initial increase in charging.The charge controlling agent is a mono azo iron complex compound represented by Formula (1): ##STR00001## wherein J represents H, alkali metal, ammonium, or alkyl ammonium, or two or more of those elements in combination.