The conventional techniques cannot set optimal energy saving modes separately for a plurality of loads and can hardly attain further suppression of power consumption. To accomplish this, in an image forming apparatus including a main circuit board which has a master CPU and controls the operation of the entire image forming apparatus, and a plurality of sub circuit boards each have a slave CPU and control each corresponding control target, the operating condition of each slave CPU is stored in correspondence with the operation mode of the image forming apparatus, and, upon being notified of the operation modes of the image forming apparatus, the slave CPU of each of the plurality of sub circuit boards sets the operation status of the slave CPU by referring to the table of the operation modes.