In order to provide a process cartridge which has a simple mechanism and can be easily positioned with respect to an apparatus body and securely mounted on the apparatus body even in a half-locked state or a half-inserted condition, the process cartridge 200 includes a unit 201, a positioning member 202, a holding member 203 and a restricting and releasing mechanism 204. The unit 201 includes an element used for an image forming process. The positioning member 202 has a positioning member which engages with an engagement portion 125, 126 formed on the image forming apparatus to position the process cartridge 200 at a predetermined mount position in the image forming apparatus. The holding member 203 holds the unit 201 to allow displacement of the unit 201 relative to the positioning member 202. The restricting and releasing mechanism 204 is arranged to restrict or release the displacement of the unit 201 relative to the positioning member 202.