An image forming apparatus which makes it possible to prevent interruption of printing due to shift to a temperature rise control mode and interruption of printing for execution of a cartridge replacement operation due to running-out of toner from occurring separately during execution of continuous printing. A temperature sensor detects that the internal temperature of the image forming apparatus has become equal to or higher than a predetermined temperature. The image forming apparatus also detects execution of toner cartridge replacement. When the temperature sensor detects, during execution of printing, that the internal temperature has become equal to or higher than the predetermined temperature, the image forming apparatus stops the printing being executed. Further, when execution of toner cartridge replacement is detected during suspension of the printing, the image forming apparatus resumes the printing being suspended.