An image forming apparatus includes a power supply control unit that performs control of switching a power supply source to an auxiliary power supply that stores therein power from a main power supply when the main power supply is off, and control of switching the power supply source to the main power supply when the main power supply is on; a detection unit that detects whether the power supply source is the main power supply or the auxiliary power supply; and a mode control unit that performs control of switching between a normal mode and a power-saving mode in which power consumption is smaller than in the normal mode. The mode control unit performs control of setting a switching time to switch from the normal mode to the power-saving mode to a shorter time when the power supply source is the auxiliary power supply.