A color electrophotographic image forming apparatus for forming a color image on a recording material, the apparatus includes an image forming unit rotatable relative to a main assembly of the color electrophotographic image forming apparatus, the image forming unit including a plurality of mounting portions for demountably mounting cartridges each provided with a developing member for developing an electrostatic latent image formed on an electrophotographic photosensitive member drum with a developer, and a transfer member for transferring the developed image on the recording material, wherein the image forming unit is rotatable between a transfer position for transferring the developed image from the transfer member onto the recording material and a mounting and demounting position, different from the transfer position, for mounting and dismounting the cartridge relative to the mounting portion in a state in which cartridges containing different color developers are mounted to the mounting portion; and a grip portion usable for rotating the image forming unit between the transfer position and the mounting and demounting position.