A fixing device includes a first heater and a second heater disposed inside a fixing rotator to heat the fixing rotator. The first heater generates an increased amount of heat and includes a first heat generator having a first heating span in a longitudinal direction of the first heater. The second heater generates a decreased amount of heat and includes a second heat generator having a second heating span in a longitudinal direction of the second heater. A partition is interposed between the first heater and the second heater to define a first compartment having an increased size and accommodating the first heater and a second compartment having a decreased size and accommodating the second heater.