There is provided an image forming apparatus which adopts a distributed control system and suppresses generation of radiation noise without increasing the cost. To accomplish this, the image forming apparatus includes a master control unit that controls the overall image forming apparatus, a plurality of sub-master control units that control a plurality of functions for performing image formation, and a plurality of salve control units that control loads for implementing a plurality of functions. The image forming apparatus performs distributed control. The image forming apparatus determines the operating frequencies of the salve control units in accordance with loads controlled by the salve control units. The image forming apparatus compares the operating frequencies of the slave control units. Based on the comparison result, the image forming apparatus changes the operating frequency of a slave control unit that is equal to the operating frequency of another slave control unit.