An image forming apparatus in an embodiment is configured to include an image processing device, a storage device, a power supply device, and a control unit. The image processing device forms an image on a sheet. The storage device stores schedule information indicating a schedule of use-time of the image processing device. The power supply device supplies power to the image processing device. The control unit is configured to control the power supply device so as to start supplying the power to the image processing device if the power supply device stops supplying the power to the image processing device at the use-time indicated by the schedule information and when a sensor provided at the installation site of the image forming apparatus determines that a detection result is a predetermined detection result.