A developing device includes: a developing unit having a developer storage chamber for storing a developer composed of a toner and a carrier, in which a developer agitating carrying member and a developer holding member capable of holding and carrying the developer agitated and carried by the developer agitating carrying member are disposed in the developer storage chamber; and an auxiliary developing unit for supplementing development for the developing unit, wherein: the developer storage chamber of the developing unit and the auxiliary storage chamber of the auxiliary developing unit are disposed adjacently via a bulkhead; a dispenser chamber that can supply or withdraw a fixed amount of developer is formed in communication with the developer storage chamber and the auxiliary storage chamber inside the bulkhead; and a dispenser member for carrying a fixed amount of developer is disposed within the dispenser chamber.