An image forming apparatus including: a fixing unit; a main power supply that provides a portion of the heaters with voltage; and a secondary power supply that provides another portion of the heaters connected to the portion of the heaters in parallel with power provided by the main power supply. The secondary power supply is disposed below and in the neighborhood of the fixing unit. The secondary power supply may be disposed between a side face of a chassis of the image forming apparatus and the fixing unit, or at an exterior of the chassis of the image forming apparatus on the side face of the chassis. The secondary power supply can be prevented from being heated by the fixing unit.