A developing device that supplies developer to an image carrier. In a developing device having a developer carrier that is driven in rotation by drive force applied to a gear provided on the shaft section thereof, the developer carrier being pressed in the direction of the image carrier, the effect of the gear drive force on the pressing force of the developer carrier onto the image carrier can be eliminated. The bearing that supports the shaft section is made slidable and the sliding direction of the bearing with respect to the direction of the drive force is set at about 90°.