An image forming apparatus for forming an image on a recording material includes a mounting portion to which a cartridge is detachably mounted and a drive transmission member for transmitting a driving force by being engaged with a drive-transmitted member provided on the cartridge when the cartridge is mounted to the mounting portion. In addition, a protecting member is movable between a protecting position where the drive transmission member is prevented from being exposed toward the mounting portion and an open position where the protecting member is retracted from the protecting position to expose the drive transmission member to the mounting portion thereby to permit engagement of the drive transmission member with the drive-transmitted member.