A cartridge used for forming an image on a recording material include a memory for storing information; 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. With respect to a direction crossing a longitudinal direction of the cartridge and crossing a thickness direction of the memory, a width of the preventing portion is smaller than a width of the memory inserted in the slit.