An image forming apparatus includes an image forming unit configured to form an image on a sheet based on image data, a control unit configured to control driving of the image forming unit, and a power supply unit configured to, if a factor for shifting from a power saving state to a standby state is detected, supply power to the image forming unit and the control unit. If a first type of factor is detected as the factor in the power saving state, the power supply unit supplies power to the control unit and the image forming unit, and the control unit restricts the driving of the image forming unit. If an instruction to perform a function of forming an image on a sheet is accepted, the control unit cancels restriction of the driving of the image forming unit.