An image forming apparatus includes a rotatable image bearing member; a plurality of rotatable developer carrying members; a plurality of developing devices in each of which a respective one of the developer carrying members is provided; and a developing device supporting member rotatable in a direction of codirectional peripheral movement with the image bearing member where the supporting member and the image bearing member are opposed to each other and integrally supporting the plurality of said developing devices. The peripheral speed of the developing device supporting member divided by a peripheral speed of the image bearing member at the time when each of the developer carrying members departs from the surface of the image bearing member and is still rubbing the surface of the image bearing member with the developer is larger than 0 and smaller than 1.