An image forming apparatus includes: a loading unit on which a toner cartridge is loaded, the toner cartridge having a first storage unit in which first information indicating at least a date of manufacture of toner is stored; an image forming unit which forms an image on a sheet; a counting unit which counts time; and a determination unit which determines whether the toner cartridge is a genuine product or not, based on how large a difference is between the first information and second information specified on the basis of a count result from the counting unit.