A digital multi function peripheral as an image forming apparatus reads, if an external storage device is connected to an external interface, a print data file including setting information concerning printing and image data for printing from the external storage device connected to the external interface, receives an instruction for change to a print setting different from a print setting based on the setting information included in the print data file read from the external storage device, and prints, if the instruction for change of the print setting is not received, the image data for printing included in the print data file according to the print setting based on the setting information of the print data file and printing, if the instruction for change of the print setting is received, the image data for printing included in the print data file according to a print setting designated by a user.