An image forming apparatus in which information regarding used amounts in image forming apparatus main bodies of different features is stored in the storage part of a cartridge, and the interchange time of the cartridge is judged by the use of the information. Thereby, even if a cartridge having interchangeability between a plurality of kinds of image forming apparatus main bodies of different features is mounted on each of the main bodies of different features, an interchange time corresponding to the main body can be grasped accurately.