An image forming apparatus which is capable of reducing the number of times a second member is separated from a first member upon entry into power-save mode, thereby minimizing failures of a separation unit. A pressure-roller separating mechanism is provided so as to abut and separate a pressure roller and a fixing roller against/from each other. The image forming apparatus is controlled to change to a power-save mode in which power consumption of the image forming apparatus is reduced. The pressure-roller separating mechanism is controlled to separate the pressure roller and the fixing roller from each other in the power-save mode based on a measurement result measured by a timer, and the power-save mode is maintained after the pressure roller and the fixing roller are separated from each other.