Disclosed is an image forming apparatus that includes a body housing having an opening and a cover covering the opening, a body frame in the body housing for supporting thereon various component parts of the image forming apparatus, an image forming cartridge receivable into the body housing through the opening to be detachably supported on the body frame and a support assembly supporting the mounted image forming cartridge. The support assembly includes a locking member movable between a locking position at which the image forming cartridge is limited in its movement along the direction of separating away from the body frame and a releasing position at which the image forming cartridge is allowed to move away from the body frame. The support assembly further includes an elastic member elastically biasing the locking member to the releasing position and a pressing member provided on the cover for pressing the locking member to remain in the locking position when the covered is closed to cover the opening.