An image forming apparatus having a power saving mode includes a first power supply configured to operate in the power saving mode, a second power supply configured to operate in a mode other than the power saving mode, a heater configured to generate heat when power is fed from the first power supply or the second power supply, and a control circuit configured to control power feeding from the first power supply to the heater and activation or stopping of the second power supply. The control circuit is configured to control, based on an instruction to shift from the power saving mode to another mode, so that power feeding from the first power supply to the heater is cut off, and the second power supply is activated to start power feeding from the second power supply to the heater.