A cartridge used for forming an image on a recording material includes a memory for storing information, wherein the memory has an outer configuration having a length in a first direction and a length in a second direction longer than the length in the first direction in a plane crossing a thickness direction thereof; a supporting portion provided on a first cartridge constituent member and provided with a slit for permitting insertion of the memory; and a preventing portion, provided on a second cartridge constituent member, for preventing movement of the memory inserted in the supporting portion. A prevention width of the slit with respect to a direction crossing the thickness direction of the memory is longer than the length of the memory in the first direction and is shorter than the length of the memory in the second direction as seen in an inserting direction of the memory.